Season 4 opens with the owner of a rum distillery murdered during a seance, stabbed in the back, while all five of the participants are holding hands to summon the ghost of a dead woman.
As it's the fourth series of this sunny bundle of murder puzzles and unspoken love (bumbling detective Humphrey Goodman is still mooning over comely Camille), the killings-of-the-week long ago slipped the bonds of any kind of realism.
