From  Acorn TV:

Inspired the beloved characters created by Jill McGown, former lovers and detectives, Chief Inspector Danny Lloyd (Philip Glenister, The Level, Outcast) and Inspector Judy Hill (Michelle Collins, Coronation Street) investigate the death of a 15-year-old schoolgirl found strangled and deserted in a public park.

DCI Lloyd and newly arrived DI Hill (who were lovers years before) investigate the murder of a schoolgirl. The girl was possibly having a sexual relationship with one of her teachers, one of whom is receiving anonymous love letters which puts his marriage at risk. This adds the man’s wife to the list of possible suspects.

From Acorn TV you can stream the 98 minutes of this full-length, one episode film.

Both quotes above from Acorn TV tell you enough about the plot which was clever enough that I twice guessed wrong about the identity of the killer.  Because of the way the two former detectives and lovers parted at the end, I suspect more episodes were planned.

Nothing special, but acceptable.