A teenage couple kiss one another goodnight when the dead body of a woman is thrown from the top of an apartment block, killing the young man. DC Bain links the dead woman to a dating agency for married people, and DI Alembic goes undercover as a client.

DI Susan Alembic and DS Luke Stone investigate the sniper-shooting of a young man in his flat, while DCs Alison Bain and Frank Craven deal with a hit-and-run killing.

One young woman is strangled as she lets herself into her flat, while across town another wakes to find her boyfriend has been shot while she slept.

A teenaged girl is found dead in her school with her wrists slashed, while a man has been tied to a tree and shot dead in the woods nearby. Stone and Alembic lead separate investigations, but is there a connection?