into a Stalker. The commander, Sathya, hopes to restore Fang's memories by showing her Hester, but the resurrected Fang doesn't recognise her nor herself. Sathya reveals that, according to her intelligence, Hester's father was Thaddeus Valentine. Tom realizes that Pennyroyal never went to America, and based his entire book on an old explorer's map in the Reykjavík library. On his way to reveal Pennyroyal's deception to the chief engineer, Tom finds out that the "ghosts" sighted around Anchorage are thieves, operating out of a parasitic submarine-like limpet attached to the bottom of the city, who call themselves the Lost Boys and work out of a larger group in the sunken city of Grimsby. With their secret discovered, they kidnap Tom and leave the city. Tom develops a sort of friendship with a reluctant Lost Boy, Caul, on their trip to Grimsby. Caul tells him that the city is ruled by "Uncle", a man who founded it as a base of thieves and keeps the Lost Boys under constant surveillance. When they arrive in Grimsby, Tom is taken to see Uncle, who tells him there is something valuable in Rogues' Roost which he wants Tom to steal for him. In return, Tom will have the chance to rescue Hester. Tom climbs a ladder up the rocky cliffs to infiltrate the base, but he is soon discovered and reunited with Hester in her cell. Realising that Uncle sent Tom to die as a diversion, Caul prematurely detonates the charges the Lost Boys were positioning inside the Roost, sabotaging the operation, but saving Tom and Hester. In the confusion, most of the Lost Boys make their way to the chamber where the Stalker Fang is kept, but the Stalker easily kills them all. She then pursues Tom and Hester into the island hangar where the Jenny Haniver is kept, but lets them escape when she seemingly recognises Tom, and then takes command of the Green Storm forces from Sathya. In Grimsby, after Uncle severely beats Caul for his betrayal, then leaves him to die by hanging, and informs the younger man that he knew Anna Fang when he was younger. Fang was a slave in Arkangel, but Uncle began to love her and released her. She betrayed him by building an airship and escaping from slavery. After Uncle was disowned by his family, he built Grimsby to make sure that nobody kept a