He says: "I think the thing about the piece is that it is a whodunit but it's got a thriller quality about it.
"It's been beautifully and rhythmically handled, both in the way it looks and its pace. | David Threlfall "It's been beautifully written and directed."
Harper's final case before retirement is an investigation into the death of Melissa Young.
Her body has been found hidden in the eaves of a flat, but the really weird thing about the matter is that nobody had reported her missing; she vanished two years ago without, it seems, anybody noticing.