Frustrated with his boring life, Wallace Avery (Colin Firth) fakes his own death and sets out to make a new life for himself as a golf pro named Arthur Newman. Along the way, he meets Charlotte (Emily Blunt), who is posing as her twin sister because her own life is too messy. Wallace and Charlotte pair up and decide to play a game in which they break into the homes of happy couples and pretend to be them. However, a large bag of cash begs the question of what Charlotte's real motives are.