When Caroline and Francis receive an offer to house swap -- from their city apartment to a house in a leafy, upscale London suburb -- they jump at the chance for a week away from home, their son, and the tensions that have pushed their marriage to the brink. As the couple settles in, the old problems that permeate their marriage -- his unhealthy behaviors, her indiscretions -- start bubbling to the surface. But while they attempt to mend their relationship, their neighbor, an intense young woman, is showing a little too much interest in their activities. Meanwhile, Caroline slowly begins to uncover some signs of life in the stark house -- signs of her life. The flowers in the bathroom or the music might appear innocent to anyone else -- but to her they are clues. It seems the person they have swapped with is someone who knows her, someone who knows the secrets she's desperate to forget.