Det. Supt. Wycliffe investigate the death of fisherman Harry Tremaine when his boat blows up just off the coast. His body is soon recovered and it is believed, incorrectly as it turns out, that his son Freddie Tremaine may have been on board. The boat was co-owned by Tremaine and local fish monger Alex Greaves and there is little doubt that Tremaine was murdered. Freddie is an immediate suspect. He runs a garage owned by his father and according to employee David Jones, likes to gamble spend money. When the police find bomb-making equipment in his flat, the case seems to be over but Wycliffe isn't so sure. The news that Harry Tremaine withdrew £500 on the first of every month for no known reason suggests to him that there are still matters about Tremaine's life that remain unknown to them.
—garykmcd