Claire has separated from her husband Steve and is now living with her boyfriend, Derek. Her daughter, Libby, tells Steve that Claire is short of money and is advertising for a lodger, so while Claire is absent, Steve is given the room by the unspecting Derek. Steve's idea is to stay in the house for a month so the Claire can judge both men on their merits; old animosities quickly rear their heads, however, and the play ends with Claire and Libby leaving the house, which Steve and Derek decide to share as bachelors. Witty, fast-moving and acutely observed, The Upstairs Cuckoo is a riotous farce with a very human heart.