On behalf of the new Perloran government, Benny visits the nomadic space fleet known as the Clutch to discuss the return of the Wishing Bone of Perlor, a priceless artefact sold to the Galyari species by the previous regime in exchange for weapons. Commander Korshal of the Security Directorate looks into the matter and tells Benny that there is no record of such a sale; perhaps Mordecan, the star gypsy who negotiated with the Perlorans, was conducting a private transaction. Korshal advises Benny to look for Mordecan in the seedy Warrens, but warns her to familiarise herself with the Clutch’s layout to ensure that she doesn’t get trapped aboard a ship that is about to disconnect from the rest of the fleet. Unable to find any helpful inhabitants in the Warrens, Benny decides not to conduct a fruitless search; instead, she places an advertisement on the general computer net, claiming to have a business proposition for Mordecan, and then settles down to wait in the local liquid plasma bar.
Meanwhile, Korshal’s son, Griko, has been attending duelling class. The other children tease Griko mercilessly about his deformities, and even his mother will have nothing to do with him; Korshal is not particularly happy about his appearance either, but he does his duty as a Galyari and a father, encouraging his son to turn his anger against his enemies. However, Griko has been suffering from growth sickness and shedding his skin with disturbing frequency. According to Research Director Tseshra, this is to be expected as Griko enters adolescence, but each bout of sickness is worse and Tseshra is starting to fear that they may not be able to contain the natural processes at work within Griko’s body. And Benny’s arrival threatens to make matters even more difficult...
Mordecan is running out of money with which to placate his creditors, and he thus responds to Benny’s ad. He is suspicious and wary at first, and puts on an Irish accent until he’s sure that she’s legitimate. She explains that the former government of Perlor traded the priceless Wishing Bone for weapons with which to defend themselves from the rebels, but it took longer to train their soldiers than they anticipated, and the rebel coup thus succeeded. Now, the new government wants their colony’s priceless artefact back. Mordecan reveals that he passed it on to the Galyari -- to Tseshra, in fact, who’d apparently asked for it specifically. Benny realises that Korshal lied to her, and decides to confront Tseshra and find out what’s really going on.
Under Tseshra’s care, Griko is recovering from his latest bout of growth sickness. Tseshra requests that Korshal send a trooper to escort Griko back to his quarters, but Benny then bursts in with Mordecan, demanding answers. Her sudden arrival agitates Griko, who attacks her, but Benny realises that she’s facing a frightened child and soothes him, calming him down. As Griko’s escort leads him away, Tseshra explains that the boy suffers from a rare bone affliction, and Benny uses this as a segue to ask about the Wishing Bone. Tseshra explains that the Galyari regard birds, their evolutionary ancestors, as sacred; she asked for the Wishing Bone in order to experiment upon it and find out whether the Galyari had an ancestral link to this ancient, extinct species, but when her research turned up negative, she lost interest and sold it on to a Skythran merchant. She offers to arrange some other form of compensation for the Perloran government, and Benny promises to consider the matter.
In fact, Benny is well aware that Tseshra is lying; the Galyari don’t usually lie to people, and they aren’t very good at it. But as she ponders her next move, she and Mordecan realise that they’re being followed -- by Griko, who has evaded his escort and tracked down Benny, who showed him kindness earlier. Benny and Mordecan try to shake him off, but he follows them into the Wardens, and when Benny looks for a guard patrol so she can hand him over, he responds violently. Disturbed, and somehow sensing that Griko is genuinely terrified, Benny decides not to hand him back over until she understands what he’s so frightened about, and persuades the reluctant Mordecan to take them somewhere safe where she can think things over.
Tseshra and Korshal discover that Griko has disappeared, and they send out troopers to search for the missing child. They must find him quickly, for his unique condition and accelerated growth means that he may experience another bout of growth sickness at any time. The Clutch’s security drones eventually spot him in the Warrens in the company of Benny and Mordecan, and Korshal sends more drones into the star gypsy territories to keep an eye on them and leads a squad of troopers to recover his son.
Mordecan has taken Benny and Griko to the star gypsies’ marketplace, a former luxury liner that has been converted to serve as the hub of the star gypsy community. While Mordecan fetches a blanket for Griko, Benny tries to comfort the agitated child -- but when she wishes aloud that she could understand what he’s thinking, she suddenly finds herself reliving Griko’s memories. She experiences the agony of his growth sickness, his inability to understand why his own mother rejects him, and his fear and rage as he is attacked by his brothers and his father does nothing to stop them, instead encouraging Griko to fight back. Mordecan finds Benny raving as if in a nightmare, and she realises that Griko has communicated with her telepathically. He is no ordinary Galyari.
In addition to this new problem, Benny still fails to understand why the Galyari are trying to keep her from finding out about the Wishing Bone of Perlor, a relic of the famous Shadow Swans of Mancor. According to legend, the inhabitants of the Mancor sector created genetically engineered skeletons around which cosmic storms could coalesce into living beings. The Shadow Swans fed on the biospheric energies of other planets, and in the process, the worlds were terraformed into conditions that would support their creators. All that’s left of the Shadow Swans now are bones, and any colony that possesses one of these bones is considered blessed, which is why the Perlorans are so desperate to get theirs back.
The lights flicker, and although Benny and Mordecan are unaware that this indicates the presence of surveillance drones, they do note that Griko is becoming more agitated, perhaps because the Galyari have particularly sensitive eyesight. But when Benny takes a closer look, she sees that the skin is peeling away from around Griko’s eyes. Mordecan realises that Griko is suffering from a bout of growth sickness, and that means that he needs professional treatment; like it or not, they’ll have to return him to Tseshra. Galyari troops then storm into the marketplace, but Benny is still unwilling to turn Griko over until she knows the truth, and she persuades the reluctant Mordecan to show them an escape route. Mordecan reluctantly leads her to the fuel pipes that connect this ship to the adjacent one, a deserted ship that the star gypsies use for storage, and promises to stall the Galyari as long as he can.
Once the Galyari have subdued the gypsies in the marketplace, Tseshra joins Korshal there to question Mordecan. He insists that he and Benny are innocent of any wrongdoing; Griko has somehow influenced Benny telepathically, and Mordecan claims that he was just playing along until he could contact the Galyari himself. The Galyari find the concept of psychic powers culturally offensive, but Tseshra is forced to admit that their prejudices mean they have no way of studying Griko to determine whether he possesses such powers. Perhaps he did somehow sense Benny’s maternal instincts and love of children, which is why he latched onto her. But if this is the case, then he’s growing more powerful more rapidly than the Galyari had anticipated, and they may not be able to bring him back. The Galyari prepare to isolate and search the adjacent ship, and Tseshra demands that Mordecan accompany them in the hope that he can talk sense into Benny.
Aboard the deserted ship, Griko is suffering from increasing pain, and as Benny tries to comfort him, sparks begin to fly off his body. Realising that she’s completely out of her depth, Benny is forced to leave Griko behind while she finds a terminal and contacts Tseshra to find out just what is happening to Griko. However, When Tseshra learns that Griko is shooting sparks of energy from his body, she realises that it’s too late to save him. Shocked, Benny finally realises that Griko is not really a Galyari -- and now that she’s broken his imprinting, Tseshra claims that he poses a threat to them all. Benny refuses to let the Galyari kill their own child, whatever he may be, and signs off, refusing to abandon Griko.
Tseshra and Korshal discuss their next move. Korshal accepts that he has no choice but to destroy what his son has become, but energy weapons will be of no use, since it was radiation that originally stimulated growth around the artefact. Korshal thus volunteers to take out the tanker with a grav-projectile rocket. Mordecan finally realises that Griko was not born naturally, but was grown around the Wishing Bone of Perlor. He begs the Galyari to give Benny a chance to escape, but they can’t risk waiting, since Griko has broken his imprinting, no longer identifies himself as a Galyari, and could tear the entire Clutch apart. Nevertheless, Tseshra allows Mordecan to contact Benny and warn her of what’s coming.
Inside the tanker, Benny returns to Griko only to find that he’s transformed into a living, shifting storm of electrical energy, raging throughout the interior of the ship. She tries to assure him that she still cares about him and she still sees him for the beautiful thing that he is, but as she speaks, Mordecan contacts her to warn her that the Galyari are going to destroy the tanker. Korshal fires the grav-projectile at the tanker, but Benny still can’t bring herself to abandon Griko. Perhaps understanding what it’s done, the storm fires bolts of energy at her, forcing her back, and she has no choice but to leave it behind and flee to safety. She dons a spacesuit and escapes out of an airlock moments before the tanker is crushed to the size of a tin can with what’s left of Griko still inside.
Benny makes no bones about her anger when rescued, but Tseshra explains that Griko was being groomed to be the perfect Galyari warrior, more powerful than any of their ordinary soldiers but without the deep-seated cultural fear that renders their race helpless against the monster known as the Sandman. Now, Korshal and Tseshra will have to answer to the Council of Directors for their failure -- and for his part, Korshal tells Benny that he’d always accepted and loved Griko as his son. Benny takes her leave, still upset but conceding that she too might go to terrible lengths to protect her children from the monster the Galyari have described. Before leaving the Clutch, she joins Mordecan for a final drink in the Warrens; the Galyari have bought him off to ensure his silence, and once Benny has negotiated a compensation deal between the Galyari and the Perloran government, she’ll return home to the Collection and her own child.