You don't wake up wanting to be someone's mistress -- somehow it just happens... You meet someone, you fall in love, it feels right but you know they're married and you know it's wrong. Set in a world where friends have become the new family, Mistresses follows the lives and loves of a group of 30-something girlfriends who met at university and are still good friends, but whose lives, and love lives, have taken very different turns. Katie and Trudi are the "grown-ups" of the group. Katie, a doctor, who had an affair with a terminally ill patient, grieves alone after his death. She doesn't even tell her closest friends what she's going through. Whereas Trudi lost her husband in 9/11 and has never really accepted his death. Their friend Jessica lives an anarchic lifestyle, which supplies a lot of gossip and humor. And then there's the happily married Siobhan -- or is she? Siobhan and Hari seem to have the perfect marriage, but their sex life and the cosiness of their relationship is starting to lose its charm, for Siobhan, anyway... From dizzy highs to extreme lows, from excitement and happiness to torment and loneliness, they're on a journey with no signposts, led by their emotions and struggling to hold it all together. This is a story about secrets and anger, passion and lust, loss and guilt. Part drama, part thriller, this is a bold take on modern life and love.