Mark Mason lives a seemingly idyllic life, but with his sons growing up and his wife, Paula, starting a demanding new business venture, he begins to feel marginalized. Mark embarks on an affair, and intoxicated by the passion this brings to his life, rents rooms in a house in Marylebone. But before Mark can begin his double life, the affair comes to a juddering halt, and worse, Paula finds out and asks him to leave. With no-where else to go, Mark hides out in his rented rooms, and suffering a deep sense of personal crisis, turns his back on his family, business partner, friends and world in general. Can Mark work out what he wants from life? Can he find a way to return happily to his old life? And will his family and friends forgive him for his betrayal?