The first case for the new unit, UCOS, is to investigate the murder of a nightclub hostess.

Disgraced detective Sandra Pullman leads a motley crew of retired detectives to identify the real killer of a young cocktail waitress murdered in 1981.

The UCOS team investigate the brutal unsolved murder of a young police woman. But as Pullman struggles to keep the boys under control, it becomes clear that this case is more personal than she's letting on. Phillip Sheppard was charged with the murder, but maintains his innocence to this day.

The discovery of a fake painting in the Queen's art collection sends the UCOS team on a hush hush mission to uncover the forger. Their investigations swiftly uncover a trail of high class frauds and suspicious deaths, but also lead to suspension for one of the squad.

The UCOS team investigate the 20-year-old murder of Josh Livesey, a young peace protestor, killed at the outskirts of a nuclear base in 1984. Is the killer one of the four secretive friends he camped with, or is the team in danger of exposing a Special Branch cover up?

The apparent suicide of a teenager from two decades ago leads the team to Wellesley Park golf club, a stronghold of snobbish male chauvinism.

When a missing person case which Lane originally investigated gets re-activated, he's determined to crack it. But when the team swiftly uncover another two mysterious disappearances, they start to think they've got a serial killer on their hands. Can Lane finally lay the case to rest?

When a desperate Halford visits a clairvoyant in the hope of contacting his dead wife, he's instead contacted by a young girl who disappeared some twenty years ago. Meanwhile the boys become paranoid when they're put through their paces: is someone out to close down UCOS?