Undercover Heart (1998)

Undercover Heart is a 1998 BBC 1 drama series about an undercover vice squad detective, Tom Howarth (Steven Mackintosh), who goes missing while investigating the murder of a prostitute. His wife Lois (Daniela Nardini), and his best friend Matt (Lennie James), who are also detectives, set out to search for him, but end up falling in love with one another.