This time around Detective Agency No. 2 is up against their biggest task so far, with no less than seven suspects. The snow is melting in Riverton, and as it does a pile of mysterious things are uncovered beneath a drift: a balaclava, a pair of gloves, a few pieces of wood, and a crowbar. What has happened? Detective Agency No. 2 soon comes across traces of a crime with many suspects. Can they find out who is behind it all?