Librarian Irene Winters is on probation after the events of The Masked City, but when rogue agent Alberich threatens to destroy the Invisible Library, it's all hands on deck, and that includes Irene and her dragon assistant Kai. She and Kai are sent to St. Petersburg to steal a book when they encounter Alberich, and it is up to Irene to stop this power-mad former librarian. Alberich has a personal vendetta against Irene, using people she thinks she can trust to further his plans. VERDICT This enjoyable series, of which three initial volumes came out in 2016, reliably combines adventure and fantasy. Clever dialog, time-hopping through fun locales, plenty of action, and hints of fresh plotting will have readers looking forward to further library missions.—MM