In the Winter of 1152, the Mouse Guard face a food and supply shortage threatening the lives of many mouse through a cold and icy season. Some of the Guard's finest--Saxon, Kenzie, Lieam, and Sadie, led by Celanawe, the legendary Black Axe--traverse the snow-blanketed territories acting as diplomats to improve relations between the mouse cities and the Guard, and find themselves on a race against time to deliver crucial medicines. This is a winter not every Guard may survive.