Wilhelm Jacobsson disappears without a trace on the Gotland boat. He is a small farmer who is fiercely independent, stubborn and constantly arguing with his neighbors. A few days later, an elderly lady is out walking her son's Rottweiler. The dog escapes, starts digging in a cairn and digs up a corpse - Wilhelm's. Maria Wern and her colleagues Hartman and Arvidsson are summer substitutes on Gotland. With the help of the local rookie police officer, who has gained their trust, the race is on to solve this puzzling case.