Rex Nihilo book 3. Spoilers ahead for the earlier ones.
In fact, it opens in media res with the plot they started at the end of book 2. Sasha is selling donuts as a cover for bank robbery (drilling into the bank, with two robots from prior books) and not feeling passionately about the revenge she is seeking. Rex cheerfully explains that she's going to force the Malarchy to hand over money to buy something already legitimately theirs, which is exactly the sort of mild pain she wants.
Then they discover the plans they are after -- for terraforming planets-- have already been stolen.
It involves a robot Charlotte Bronte, jumping from buildings, Pepper's old debt to the Ursa Minor Mafia, a sort of sister to Sasha, a not so secret auction, memories, a wandering wormhole, what the lack of a thought arrester will do, and more.