On their first day of training with the London Metropolitan Police, three recruits are assigned to a team of undercover detectives. Their dangerous mission is to become criminals in order to bring down one of the world's most notorious drug dealers, Den Donovan, alias 'Tango One.' But as the undercover recruits inch closer to their target, they each are drawn in by the charismatic criminal leader. Directed by Sacha Bennett, this crime thriller is based on the acclaimed novel by Stephen Leather.