Book 3 in James Moloney's page-turning Doomsday Rats series. Berrin has been one of only a handful of humans to escape the control of the evil Malig tumora. But when Berrin emerges onto the creek bank after a scorpion-like cannon has flooded the tunnels, Malig tumora's servants, the gruesome-looking Gadges, recapture him. Imprisoned within Malig tumora's menagerie, Berrin meets Aden, an unusual boy with a powerful learning ability. together, the boys face many challenges as they complete a series of tests aimed at identifying a suitable clone that will make all remaining humans obsolete. But Berrin and Aden face a more immediate threat when they come face-to-face with Malig tumora's most terrifying creation: a computer that turns against its own creator, successfully enlisting the support of the Gadges in return for a blood promise. Berrin's mission intensifies as he sets out to find the moths that are capable of destroying the purple flower, the fragrance of which controls the humans under Malig tumora's power. When all hope seems lost, can the boys escape the bloodthirsty Gadges and complete the task of saving humankind from a horrifying fate?