Director Michael Grandage adapts Bethan Roberts' 2012 ménage à trois novel predominantly set in the 1950s United Kingdom. The story follows policeman and schoolteacher Tom (Harry Styles) as he meets and falls in love with Marion (Emma Corrin) while living on the Brighton coast. Tom later meets a new person in town, Patrick (David Dawson), who moved there to heal himself from the loss of a partner. The two men soon develop an attraction and start an affair, regardless of homosexuality's illegality. But the three try to continue their entangled lives despite the challenges.