You don't wake up wanting to be someone's mistress - somehow it just happens. 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. But their lives have taken very different turns. Katie, a doctor and the 'grown-up', has been having an affair, with one of her patients. Whilst her best mate Trudi is grieving the loss of her husband killed in 9/11. And there's Jessica - her anarchic lifestyle supplies lots of gossip and humour - but is there more going on than even her closest friends now about? And then there's happily married Siobhan - or is she? Part drama, part thriller, this is a bold take on modern love.