Shona McMonagle is your ordinary, garden-variety librarian: comfortably padded, in her middle years, expert in various arcane martial arts. She also has an impressive knack for time travel (“impressive” may be overstating things: her first two forays—revolutionary Russia, 19th-century France—went less than smoothly).
Her latest mission? Head to 11th-century Scotland, cozy up to Macbeth and Lady M, prevent them from murdering Duncan. In the ordinary course of things, this would be a doddle. But then there are the witches, who prove remarkably quick to take offense. And the business of being turned into a mouse. And the fact that the mission is in truth threefold. One, keep Duncan alive and kicking; two, correct the historical record and lay bare the ludicrous lies introduced by that silly Shakespeare play; and three, burnish the honor of the Marcia Blaine School for Girls, the finest institution of pedagogy in the greater Edinburgh area. Can she do it? Of course she can! NEVER UNDERESTIMATE A LIBRARIAN!