John and Gillian meet their grandfather, "Doctor Who". Together they travel to thirtieth century were they meet the peaceful Thains. The Thains are being attacked by the evil Kleptons in their flying machines and by their destructive creeper plants.

A fault develops in the controls of the TARDIS, and Dr Who tells John and Gillian that as a result the time and space machine will materialise prematurely. Above the surface of a barren asteroid, a rock hurtling through space collides with the spinning TARDIS, sending the craft plummeting down. The TARDIS smashes into the surface of the asteroid, damaging the controls, and Dr Who fears that they could be marooned there permanently. They discover, on leaving the TARDIS, that the asteroid has low gravity, and also that they may not be alone, since a small rocket ship has come to rest some distance away. The three are making their way towards it when a large, scaly creature reminiscent of a dinosaur comes into view and bears down on them. The gravity level, however, allows them to make a big leap towards the rocket, which they now perceive to be damaged as well, most likely from a similar crash landing to their own. They climb in through its hatch before the creature is able to get there. Relief is short-lived, though, since a diminutive, humanoid astronaut with a bald head and large eyes flourishes a tubular ray gun and threatens to reduce them to atoms.

Dr Who calms him down, explains that they too have crashed in this wild place, and suggests that they work together to achieve their respective escapes. The astronaut tells them that his name is Grig, and reveals that he is from the planet Theros, where a mysterious disease has broken out and is gradually weakening most of their race. Grig, one of those unaffected, had set off into space at the request of the President in the hope of discovering a planet where an antidote was known, but his ship was forced down onto the asteroid after encountering a storm of meteorites. The craft’s systems were affected, and he is therefore stranded. He asks if they might all escape in the old man’s ship, but the Doctor discloses that the controls of the TARDIS are damaged too. The reptile outside attacks the rocket, shaking it and battering its hull still further, so Dr Who sets about fixing the instruments in the hope of lifting off before the creature wrecks the craft. Just as destruction seems inevitable, Dr Who completes his work and the ship blasts off, escaping both asteroid and monster. Unfortunately, the TARDIS has been left behind as well. The Doctor and his grandchildren, resolved to help the Therovians if they can, now head for Theros with Grig.

They find that the situation has worsened, and that the President himself is now very ill. There is one glimmer of hope though: the oldest and wisest member of the Therovian race, Wopan, has learned that a certain moss, to be found only on a planet called Ixon, may provide the antidote they need. Dr Who, John, Gillian and Grig leave forthwith on their new quest. After many weary days of space travel, Grig’s ship touches down on Ixon, a bleak and forbidding wasteland of ice. As they open the hatch to leave the craft, they find a group of flint-eyed, sharp featured warriors awaiting them, one of whom informs them that strangers are not welcome, and that they are to be taken to the Great Ixa for questioning.

Dr Who points out to his group that they are outnumbered and have no choice but to comply, and that in any case it might be as well to put the Therovians’ plight to the ruler of this planet and ask for help in locating the moss. With the grim soldiers, they board an open-topped metal car and are soon skimming across the hard-packed ice. The vehicle enters a large cavern hung with sumptuous drapes. On a high-placed throne sits a truly forbidding figure, robed and crowned. Dr Who explains the situation that has led to their visit to Ixon, and surprisingly the Great Ixa agrees to the moss being collected, so perhaps appearances are deceptive. Ixa informs them that the moss grows only in a network of underground caves connected by tunnels, and that the travellers must gather it themselves, since the Ixons have always been superstitious about these particular tunnels and few have ever ventured into them. One of the metal cars and some warmer clothing are provided for the use of the visitors, though, together with directions to a particular cave mouth and the tunnels. Clad in their borrowed furs, Dr Who and his party set off in their transport. The Great Ixa watches them go with a mirthless smile. He has another, hidden agenda.

Some way into the tunnels, the track that the travellers have been following ends and they are obliged to finish the journey on foot. Dr Who remarks that the temperature has not risen at all – Ixon must be a solid ball of ice. Passing into a large cavern with a yawning crevasse across it, they see the exuberant moss growing all along one of the pitted walls and begin to gather as much of it as they can carry back to their vehicle between them. The Doctor suddenly notices a long-horned bison-like creature that has entered the cavern and is watching them intently, prior to making its charge. Grig proves surprisingly wiry for such a small being. Having seized the animal by the horns, he single-handedly pitches it into the crevasse. The four make for the ice car, each with an armful of moss. On their return a group of Ixon guards are waiting and conduct them back to Ixa’s throne. The Great Ixa laughs scornfully at their foolishness. Now they have collected the moss, he intends that the Therovians should pay for it with all their wealth.

Dr Who denounces Ixa as a treacherous villain, strikes a handful of his everlasting matches and sets fire to the drapes looped across the cavern wall. The heat throws up a thick cloud of smoke from the ice, which enables the Doctor and his companions to evade the guards, commandeer an ice carriage and head for Grig’s spaceship. The Ixons open fire as the travellers climb aboard carrying the moss, but Grig succeeds in lifting off before his craft is damaged. Many days later they arrive back on Theros, where scientists set about extracting the antidote from the moss. The resultant liquid restores the Therovians. Grig returns Dr Who and his grandchildren to the asteroid where they left the TARDIS, and after the Doctor has effected repairs to his craft and farewells have been made Grig watches as the machine whirls away into space.

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Reprinted in Doctor Who Classic Comics #12

The TARDIS lands on a mist enshrouded space station which belongs to space pirate, Thrax. Using a machine, Thrax is capturing supply ships and selling their cargo for his own profit.

On the lunar-like planet Vortis, the TARDIS lands beside a huge boulder and near an enormous crater. Dr Who announces to his grandchildren, John and Gillian, that he has visited this world before, when he helped to defeat the giant ants called Zarbi. No sooner have the three left the TARDIS than they see two of the creatures – and to the Doctor’s amazement they are flying! He has barely commented to John and Gillian about this when the Zarbi demonstrate another new feature: a sting weapon powerful enough to blast a rock to pieces.

The butterfly-like Menoptera, the Doctor’s allies in his previous struggle, arrive on the scene. Generations have passed, but the Doctor’s name is still remembered. The Menoptera describe how the Zarbi, after their brain (a reference to the Animus of the television story) was killed, worked with them to till the soil and make Vortis habitable again. Then new problems arose: the Zarbi became rebellious once more and unaccountably developed the power of flight.

The Doctor accompanies the Menoptera to the hills, where Zarbi activity is centred. On the way they come across a deserted alien spacecraft and realise that there must be other beings on the planet. Moving on, they reach the Zarbi base: a mushroom-shaped metal tower encircled at some distance by a deep trench. John picks up a rock that is shot with veins of what Dr Who identifies as Galvinium X, a very rare and valuable mineral with powerful qualities. If the Zarbi made weapons with it the armaments could be terrifying.

A non-flying Zarbi appears and menaces Gillian. They manage to overpower it, but a huge group of the creatures is approaching. The Doctor notices a pile of mined Galvinium X near the edge of the trench. While the Menoptera swoop into the air and distract the attention of the Zarbi, Dr Who edges nearer to the mineral and uses a Menoptera weapon to ignite it. There is a huge explosion that scatters the Zarbi. Triumph, however, is short-lived: the flying Zarbi now swoop down to attack. One is shot down, but another seizes the Doctor and flies off with him.

A Menoptera follows and watches as the old man is taken into the mushroom tower via a roof hatch, then returns to John and Gillian with the news. John’s attention is then caught by the flying Zarbi that was shot: a spindly hand is emerging from a hole in its underside. The flying Zarbi are fakes, flown by the alien Skirkons, one of whom now comes fully into view: a skinny creature with a face reminiscent of an owl’s.

John and Gillian, upon whom everything now seems to depend, squeeze inside the abandoned Zarbi shell and succeed in piloting it to the mushroom tower and in through the roof hatch. Leaving their camouflage, they locate the Skirkon control room, where the Doctor is secured to a metal bench. A laser beam is moving inexorably towards him.

The children free their grandfather, but are spotted by the Skirkon leader, Zarka, who is forcing captured Menoptera to quarry Galvinium X. Dr Who has noticed a small machine topped with a transparent dome, and believes it to be a contrivance with which Zarka controls the real Zarbi. Before he can be prevented, the Doctor hurries to the machine and deactivates it, releasing the creatures from the device’s power. 

The time travellers escape in two of the flying Zarbi outfits, but Zarka warns via a loudspeaker that he still has the whip hand and has given orders that the humans, and every one of the Menoptera, are to be ruthlessly mown down. The flying Zarbi begin to leave the tower to carry out the instructions, but the Doctor turns his own Zarbi disguise back towards the Skirkon base and operates its sting gun, aiming for piles of Galvinium X which are very close to the tower. They all explode more or less together, taking the mushroom tower and the Skirkons with them and creating a spectacular conflagration.

Later, the Menoptera bid farewell to Dr Who and his grandchildren beside the TARDIS. Soon afterwards there is a sudden rush of wind and the time and space machine disappears.

The Doctor and his companions land on a planet ruled by spherical robots called Gyros. When Gillian is captured the Doctor investigates and discovers a race of humanoids who are the survivors of a terrible illness. It soon transpires that the Gyros are the servants of another group of people who sealed themselves inside a building to avoid infection from the disease.

The TARDIS lands in the strange magical land of the Pied Piper of Hamelin where the Hamelin children are still prevented from returning to their parents. After making a treacherous journey to the Piper's castle the Doctor is set three challenges which, if he passes, the Piper will allow the Hamelin children to return home.

In 1970, the first men from Earth land on the moon. The two astronauts are however dismayed to discover a Police Box. Going to investigate the astronauts fall down a crevasse.

When the TARDIS lands on a small rock in the ocean, the Doctor, John and Gillian are amazed when they discover that all about the time is flowing reverse. Separated from the TARDIS, the Doctor realises that the only way back to it is to retrace their steps back to the beginning of an adventure that they have no knowledge of.

Landing on a barren rocky world, the TARDIS is stolen by a giant lizard creature. Attempting to recover the ship, the Doctor and his companions are then captured by more lizard creatures.

The TARDIS lands on the planet Demeter where the travellers are taken to be an invasion force from the neighbouring planet, Bellus. Shortly after the misunderstanding is cleared up the real attack from Bellus takes place, with vibrations shaking Demeter, causing mass destruction.

The Doctor, John and Gillian land on the planet Go-Ray where the entire planet is powered by Cardium. As the doctor and his grandchildren approach the Cardium HQ an explosion takes place causing the power supply to fail. The travellers are blamed by strange, wheeled Go-Rays who imprison them.

Landing on a planet, the TARDIS is drawn through quicksand by a race of small frog people and used as bate in a trap for a shark. The Doctor, John and Gillian help the frog people but lose the TARDIS once again, this time along with Gillian. It is up to John and the Doctor to rescue her and escape from the realm of the Ancient Mariner.

Fed up of noisy aeroplanes at the North Pole, Santa Claus has moved to another planet where he is making toys for Christmas. Santa has had many requests from children for model TARDISes and the Doctor decides to help by using a device that he calls his 'magic box'. However, Santa's Christmas preparations are threatened by the evil Demon Magician and it is up to the Doctor, John and Gillian to save the day.

The Doctor, John and Gillian meet an animal collector who has lost a valuable bird called a Didus. The Doctor agrees to find the bird for the collector and the three travellers set off into the jungle. There, they encounter a hostile tribe who have captured the Didus believing it to be a lucky mascot.

The Doctor, John and Gillian land on Space Station Z-7 which has been taken over by rebels. The rebel leader is eager to learn how the TARDIS was able to penetrate his protective mine field and straps the Doctor into a truth machine. It is up to John and Gillian to escape from their cell and rescue the Doctor.

The TARDIS lands on Trodos in the year 2066 where the Doctor and his companions are immediately taken prisoner by the robot Trods. The Trods have subjugated the human population and now use them as a slave work force. The travellers manage to escape from their prison and together they confront the ruler of the Trods - Super Trods.

The Doctor and his grandchildren land on the planet Gemina which has been devastated by a war with its neighbouring planet, Gemino. On meeting the survivors, the Doctor offers to help open the sealed 'Vault of Plenty' where all the planet's food supplies and knowledge are held. The Doctor, John and Gillian have to solve a variety of challenging puzzles and the price of failure is death!

Landing on the legendary Haunted Planet, the Doctor and his companions make their way to a space age castle. There they discover the evil Zentor who is planning to hold the Universe to ransom with a deadly gas.

Landing on the planet Zerox, the Doctor leaves John and Gillian in the TARDIS and goes to explore. Captured by the native, the Doctor is forced to battle a strange beast in an arena for the amusement of the native's Emperor. The Doctor manages to defeat the creature and escape but he is pursued by the Emperor and his men in a manhunt!

The TARDIS lands underwater. Wearing special breathing masks and flippers, the Doctor, John and Gillian explore the marine world. However, they are soon captured by a giant underwater robot which is powered by slave labour and controlled by an evil professor.

The TARDIS is drawn off course and materialises in a futuristic space city. The Doctor and his grandchildren are horrified to discover that they are up against their old enemies, the Trods. The Trods have been reactivated by another space traveller who is controlling their actions. The Doctor, John and Gillian are forced to enter the buildings of the city which are full of traps.

The TARDIS lands at the Galaxy Games. The games have been dominated by a competitor from the planet Klondite. However, the Doctor realises that even the Klondite is a poor athlete by Earth standards. The Doctor enters John in a game as Earth's representative. However, the Klondites attempt to stop john from competing by kidnapping him.

When the TARDIS lands in a crater, the Doctor and his grandchildren are immediately taken prisoner by the 'Master Race'. The Master Race use the travellers and other prisoners to test their new scientific advances.

The Doctor and his grandchildren discover a group of space travellers imprisoned on the planet Spekra. The Doctor fights the evil plans of the dictator, Gritog, and a variety of dinosaur like monsters.

The Doctor, John and Gillian arrive on a south sea island on Earth. There they escape from an erupting volcano and discover King Neptune who rules his domain from inside a giant sandcastle.

The Doctor, John and Gillian arrive on the Planet Zeno which they discover to be inhabited by the legendary Gorgon.

Two Earth astronauts lose control of their rocket ship, which is drawn down to the surface of a desert world scorched by an enormous sun.  Leaving the craft, they are almost immediately aware of a machine swooping through the air towards them.  

Soon afterwards the TARDIS lands near the now abandoned ship, beside which is the word HELP written in the sand.  John enters the deserted craft and emerges with a flare gun he has found.  A creature in a flying bubble machine arrives on the scene and bears down on them.  The travellers immediately identify it as a Klepton, one of the race they met and defeated during their first adventure together (The Klepton Parasites).  John uses the flare gun to defend them, the bubble cracks and the distracted Klepton loses control of the machine, crashing it.  The three remove the stunned creature and board the damaged machine, which is still usable.  

Travelling over the desert, they reach a flat-topped pyramid and fly into it via a hatch that opens automatically at their approach.  Unfortunately, the Kleptons are well aware of what has occurred and capture Dr Who, John and Gillian as they leave the bubble craft.

The Klepton leader tells the Doctor that their world has moved too close to the sun and become uninhabitable, and that they need a new home.  They have learnt of the planet Earth and insist that Dr Who helps them to plan an invasion.  When he refuses, he is placed, with John and Gillian and the two Earth astronauts, in a large open-topped crate that is suspended from the roof over a vat of boiling oil.  The sides of the crate are of metal, but the bottom is made of only basket-like lattice.  

The astronauts have also refused their help, but point out to the time travellers that if they all persist in opposing the Kleptons the obvious is going to happen: the crate will be dropped into the bubbling oil.  John, who still retains the flare gun, aims it at the oil and fires.  A thick cloud of black smoke rises from the vat, and John urges his companions to swing the crate back and forth.  They grab the edge of the vat and between them manage to hold the crate there while they all climb out of it.  Under cover of the smoke they board two of the bubble craft and leave by way of the automatic hatch.  

The Kleptons are soon in hot pursuit, but in their haste they omit to reactivate the equipment they used to draw the Earth ship to the planet and hold it there, so the astronauts are able to lift off as the time travellers watch.  Dr Who, John and Gillian have a rather narrower escape, the TARDIS vanishing just as the Kleptons reach it.  Inside the ship, Dr Who expresses the hope that they will arrive at a friendlier place next time.

Caterpillar men invade Earth and capture a group of world's leading scientists. The TARDIS lands and the Doctor is also captured.

The TARDIS materialises on an unmanned boat which carries a deadly bomb as its cargo. Trapped within the boats forcefield, the TARDIS is unable to take off. The Doctor must devise a way of disabling the force field and diverting the vessel before it hits its target.

The TARDIS makes a stop on a lush green world. After scaring of an ugly cat like creature, John and Gillian are captured and imprisoned by a race of giant birds.