Gwendolyn, the Matriarch and undisputed leader of the Mouse Guard, has summoned a newly-formed patrol to her quarters in Lockhaven. The patrol is informed of their duty: deliver a bundle of time-sensitive communications to several towns in the Territories including Elmoss, Sprucetuck, Dorigift and, finally, Gilpledge.
It is a long way to Gilpledge, and any number of things could happen to delay the patrol in their appointed task. How will this new patrol handle what will be placed before them? Will they rise to the occasion or slip in the melting snow of early Spring?
Under the questioned command of Casey Marsh, aging weather watcher, the patrol departs from Lockhaven at dawn, making their appointed rounds with little fanfare or excitement. The spring thaw has progressed nicely, it seems, and many of the local militias and town constabularies have already cleared the main roads from Lockhaven to Elmoss, Elmoss to Sprucetuck, and Sprucetuck to Dorigift. Unfortunately, the further south that the patrol travels, the more that winter seems to be hanging on. Casey rises to the occasion, attempting to use her extensive experience in the field to find the safest way through the melt water and lingering snow drifts. The grizzled, hardened veteran Aldred lends his input, directing Freddy Adams where to dig a trail.
Despite the patrol’s best efforts, and despite Prudence Fern’s best attempts to find the trails of local wildlife, the party unwittingly finds itself in the makeshift nest of a raven. The wily bird attempts to make off with the mail bag, but due to the quick, fearless actions of Freddy and the rest of the patrol, the Raven departs, squawking, with nothing but a torn scrap of the bag and one less eye.
With a bloody Aldred and a handful of soaking wet cloaks, the patrol finally arrives in Gilpledge, content to deliver the last of the mail and have a few hours to themselves. Before they can retire, however, an unassuming mouse by the name of Martin, a carpenter, approaches the patrol with a dilemma. With little argument, the patrol offers to assist Martin with the recovery of a precious family heirloom from the abandoned ghost town of Walnutpeck, located just outside the Scent Border in a dangerous, weasal-occupied region known as the Darkheather.
Given the night to rest and recuperate, each guardmouse goes his own way. Aldred secures lodging for the patrol in a modest, yet comfortable establishment. Casey and Prudence see that a suitable report is written and set to be delivered to Lockhaven come morning. Meanwhile, Freddy samples the local brews. For now, the guardmice are comfortable, but who can say what the morning will bring? The journey to Walnutpeck is a long and arduous one.