Petersen's intricate medieval world of wee warring animals gets a prequel to the main story line of Fall 1152 (2007) and Winter 1152 (2009). In 1115, the gruff old hermit warrior Celanawe was a much younger mouse and embarks on a treacherous quest across a sea and into unmapped ferret territory to find the fabled Black Axe. Though Black Axe works well enough as a stand-alone adventure, Celanawe's origin story promises plenty of revelation to readers familiar with Mouse Guard lore. Still, both newcomers and fans alike will find much to explore in Petersen's finely wrought artwork, high-stakes intrigue, and derring-do tale.