Fugue

July 1965, and Oxford is in a gothic mood. A menace stalks the city, and at first the attacks read as the work of a deranged lunatic killing at random. Morse digs deeper and finds the method under the madness: the crimes are staged with care, elaborately, and the staging points to a killer who shares his passion for opera.

The taunts arrive at the Oxford Mail as cryptic letters goading the police over their failures. The body count climbs while the city police scramble to find the next victim. Morse, it turns out, has finally met his intellectual match, and only a detective of his peculiar mind can break the clues.

At the climax he saves Thursday from being thrown off a college roof. His reward is reinstatement to general duties, and a shaken sense of what he is doing with his life. The show has never been shy about the cost of being clever.

Russell Lewis wrote it and Tom Vaughan directed. Shaun Evans is Morse, with Abigail Thaw as Dorothea Frazil, Laura Rees as Faye Madison, Will Featherstone as Phillip Madison, Geoffrey Streatfeild as Dr Daniel Cronyn, and Lex Shrapnel as Roy Adamson.

The episode gives Thursday a proper scare and gives Morse a proper lesson: even winning this game leaves a mark. The gothic Oxford nights are shot beautifully, all wet cobbles and long shadows, and the menace stays tastefully off-screen until it needs to be on it. The letters to the Oxford Mail are a fine touch, taunts posted in plain sight.

You do not need to know your way around an opera house to follow it, though it helps with the flavour. It is an opera of an episode, staged in the dreaming spires, and it announces the series' favourite game: a killer smart enough to play with the police, and one detective smart enough to play back.