Passionate defence barrister Martha Costello faces challenging cases and surprising clients, which test her faith in the criminal justice system. Gifted colleague Clive Reader is called to the bar with her. They work hard with pupils, Nick Slade and Niamh Cranitch, but ultimately only one can eventually be taken on as a member of chambers.

The lives of three couples in different stages of their relationships are followed: Dickie and Babs are married, Clint and Abbey are single, and Eddie and Lillie are in the ‘other’ category — together for years but never wed.