Eva and Kat are a couple coming to terms with the death of their cat when Kat's close friend Roger comes from Barcelona to stay and party.

Space is tight on their London houseboat and Eva is initially not best pleased to have the gregarious, womanising Roger impinging on their space, but then she hits on a plan that will bind the three of them together and sets about executing it with a renewed sense of purpose.

However, as the stark reality of her plan becomes more apparent, its effects begin taking their toll on the couple, plus their friendship with Roger and relationship with Eva's mother, Germaine. Their unusual situation looks to put everyone to the test.