A swanky new gym has opened in leafy south-west London. Four women bond over push-ups and Pilates and become firm friends.

Percy likes sorting out other people's problems, but her own life is a shambles, with a terrible secret addiction. Can she kick it and win back the love of her husband?

Patrice, wealthy but damaged, wants another baby, but husband Jonty isn't interested in sex. Is it her imagination, or is he getting too close to the husband of one of her new friends?

Carmen is living dangerously, determined to get pregnant by her cold, treacherous boyfriend. She doesn't see what is under her nose until it's nearly too late.

Suzanne adores her sexy second husband, but is she neglecting him for her job? And has she realised what is happening to her teenage daughter?

New best friends. Their friendship is about to be tested to the limit.