The Tailor

From publisher blurb:

The Tailor is a good and honest worker. He does his time. He keeps his head down and his nose clean. He doesn’t bother anyone and he doesn’t ask for anything in return. He is always at home when someone needs him and he never refuses a request for help. The Tailor is everything the Black Monk expects from his prisoners. There’s never any drama here. Lately, the Tailor has been asking strange questions, working long hours, and generally breaking his old habits. Yesterday he was seen measuring a mule and carrying wood back from the forest. What kind of clothing requires two trees?