Set in the year 1152, the Black axe is a prequel to the previous two volumes of Mouse guard and tells of Celanawe's epic quest to take possession of the black axe.

Follows the adventures of Lieam, Saxon, and Kenzie, three mice who are part of the Mouse Guard--soldiers and guides for common mice looking to journey from one hidden mouse village to another--and their quest to uncover a traitorous plot against the Guard.