
In the early 1990s, Her Majesty’s Customs and Excise was losing its battle with illegal drug smuggling across Britain’s borders. In a top-secret operation, a small team of Customs employees were sent undercover with new identities and told to infiltrate Britain’s most dangerous drug gangs.

As drug deaths surge in '90s Britain, the government turns to a veteran customs investigator to recruit a novice unit for an unprecedented covert mission.

Customs recruit Guy faces tests that threaten to blow his cover. Meanwhile, the team in Liverpool chase the scent of a suspicious bakery.

A volatile alliance puts Guy at the heart of a high-risk smuggling deal. The Legends in Liverpool embark on a surveillance mission that ends in trouble.

Cracks start to appear in both gangs as tensions, pressure and paranoia run high. Kate looks to exploit a possible weakness in Carter's armour.