After a long but peaceful winter, Gwendolyn’s given Ealdwyn his first unofficial mission of the year. It turns out she’d dispatched a patrol led by a mouse named Clarke to the town of Windselm at some point last year to investigate some mysterious disappearances in that area. Clarke and his mice never made it back to Lockhaven before the snow fell, and winter being as dangerous as it is, Gwendolyn deemed it too risky to send any other mice after them. Now that the first thaws are here, she’s alluded to the idea that Ealdwyn should go and check up on the goings-on in Windselm; perhaps a more experienced guardsmouse can uncover the truth behind the disappearances, and mayhap even discover what’s happened to Clarke’s patrol.
Ealdwyn gears up for the journey, and (avoiding a run-in with Laurel) sets out onto the trail. It becomes immediately apparent that he is one of the first guardmice to leave Lockhaven: no mice have yet tended to the washed-out roads and trails, making travel that much harder.
The first leg of the journey passes without incident, and Ealdwyn is afforded some time to see friends and family when he spends the night in Shaleburrow. In addition to room and board, his parents give the guardmouse a partially-completed map of a trail from Shaleburrow to Windselm, and he takes the detour hoping to save time (and maybe fill in some missing details while he’s at it). Soon, however, it becomes apparent that this map isn’t very accurate, if it’s even detailing this supposed route.
Ealdwyn spots what appears to be a deer trail leading off through some underbrush, and curious to see if it would provide a better path, he follows it. As evening draws near, the trail ends unexpectedly in a dale still littered with small snowbanks. The wayward mouse settles in for the night amid some ash roots jutting out of the ground, while a cold spring rain begins to fall.
The next morning, though, the rain is still coming down. Left with little other choice but to continue on despite the rain, Ealdwyn musters his gumption and sets out. The rain drenches the poor guardmouse for most of the day, finally breaking in the late afternoon. Consulting his map shortly after, he discovers that he’s reached a large cedar that serves as a landmark on the new trail. Heartened despite his utter exhaustion, Ealdwyn journeys on into the gathering night and arrives at Windselm.
He is met by a watchmouse who, after lowering the lift and allowing him entry to the upper reaches of the elm, cautions him that the Mouse Guard are not well-received in Windselm. The watchmouse goes on to relate that the last patrol of guardmice near town vanished; though the townsmice assumed they had simply departed without notice, he knows that no mouse o’ the watch saw them leave. Advising Ealdwyn to hide his cloak and pass himself off as any ordinary mouse, he lists the various inns and hostels in town, and the guardmouse heads for the Toothless Weasel. Once there, he finds sparse fare and cramped lodging, but decides it matters little given how weary he is and settles in for the night.
His sleep is broken by the sound of whispering outside his room. Waking enough to listen, Ealdwyn makes out the hushed word “guardmouse” and decides that caution is appropriate. He climbs carefully and quietly out of bed, hefts his greatsword, and moves to the far end of the room. When two mice sneak in and begin searching his bed, he boots the door shut and confronts the interlopers at the point of his sword!
It becomes immediately apparent that the intruders – a ladymouse and a gruff bigpaw – haven’t come to try to bash Ealdwyn’s face in. Prompted by the guardmouse, the two mice introduce themselves as Briallyn and Glynn, and Briallyn tells Ealdwyn she’s come to ask his help in secret. Curious, Ealdwyn agrees to aid the mice, and so the trio sets off into the night, making their way through the twisty tunnels of Windselm out along the elm’s branches and down a stairwell carved into its trunk. As they proceed, the ladymouse speaks of a patrol of mice who’d disappeared mysteriously in the fall. She alludes that she and Glynn had found something very recently that might give a clue as to the patrol’s fate, but will say no more.
Finally, the trio approaches a small clearing where a fallen birch lies. Glynn announces their arrival, and a trio of weasels appear from behind the birch! Ealdwyn stands amazed and the bigpaw seizes him, but the guardmouse quickly draws his knife from his satchel and wounds Glynn enough to escape. He bolts off into the night, with the weasels in hot pursuit.
Outrunning the weasels, the guardmouse makes it back to the lift station; his strength leaves him atop the tree, and Tucker – the watchmouse from earlier – finds him swooning from exhaustion. He awakens later that morning in the guardhouse, with Tucker all but demanding answers: where was he, that he arrived so late last night? and why was his blade caked with blood? and above all, what was going on?
Deflecting his questions, Ealdwyn learns that Briallyn is a baker, so he finds her shop. Glynn’s with her, belly freshly bandaged, and after a tense standoff the guardmouse has his answers. The conspirators reveal that last summer, several weasels settled in the area, attacking travelers on the roads. Glynn led many of the town’s watchmice in an offensive against them, but their efforts were fruitless. The weasels told Glynn that they wanted some twisted form of tribute: in exchange for sparing the town, the townsmice would offer some of their own number to the weasels. They made it plain that if their terms were rejected or the townsmice sent for aid, they had no qualms destroying Windselm. Snatching up the rest of the watchmice, the weasels left Glynn alive to carry his message back to the townsmice…but he came to Briallyn first, and the two of them decided that for the sake of the town, none else could know what had happened. When Clarke and his patrol came snooping about, they gave them to the weasels, both to keep their terrible secret and to satisfy the weasels’ hunger through the winter.
Thoughtfully quiet, Ealdwyn thanks the pair for finally divulging the truth, and leaves. Realizing that if the weasels recognize him as he departs the town they’ll descend upon it, the guardmouse fashions a disguise and sets out for Lockhaven with all possible haste.
Arriving, he hurriedly draws up a report and sends it off to Gwendolyn, then falls in a heap in the first available bunk he can find. He sleeps – truly sleeps – for the first time in days. He’s woken by a tenderpaw bearing a response from the Matriarch: “Carry on.”
Resolving to do just that, Ealdwyn calls upon Caradoc, a veteran of the Winter War and a skilled tactician, and confides to the guard captain that weasels threaten Windselm and must be stopped. At length, Caradoc agrees to bring his patrol (and a couple mice besides, if he can muster them) to Windselm and deal with the weasel threat. To help, Ealdwyn stops by the outfitter’s to buy gear and supplies for Caradoc’s squad and thereby minimize both red tape and inquiries that a requisition might prompt. Bertram, the shopkeep, gives the guardmouse a wickedly hard time about his wanderings to and fro, accusing him of shirking his duties and leeching off the Guard’s largesse. Ealdwyn literally drops the gear off with Caradoc’s patrol and departs, seething.