Everyone on the space station believes Rat was killed in the battle with Nanny, a terrifying robot run amok. That’s fine with Jeff and Rat. They are relieved that Nanny was destroyed. But was she? As suspicions mount that Jeff is sheltering Rat, Dr. Vivexian, the scientist from whose lab she escaped, heads to the station to find her. Meanwhile, despite Jeff’s warnings, Nanny is being repaired. Rat is determined to remain free, but a resurgent Nanny threatens everyone on the station. With the help of LB, Dr. Wagg’s experiment in AI, Jeff and Rat search for a way to destroy the insane Nanny while keeping Rat out of Dr. Vivexian’s clutches. In this sequel to Space Station Rat (2005), Daley presents another entertaining outer-space romp in which the most vivid characters happen to be artificial. While the story is a mite thin on setting and characterization, the fast-paced plot is sure to please fans of computer games and sentient machines and serves to expand the rather skimpy field of middle-grade science-fiction books. (Science fiction. 8-12)