In 1989 someone is threatening to steal the crown jewels, so the Queen of England summons Mac B. to England to protect them--and when they are stolen from a locked dungeon cell, where Mac and Holcroft, one of the warders, are supposed to be guarding them, it is up to Mac to figure out how they were stolen, and whether the thief is the descendant of an Irish soldier-of-fortune who tried to steal them in 1671, or someone else entirely.

There is a legend that if the ravens at the Tower of London ever leave then Britain will fall, so when somebody steals the birds, the Queen calls for Mac B. to find the thief and retrieve them--a mission that takes him to Iceland, where he encounters secret submarines, hungry polar bears, and his arch-nemesis from the KGB.