Mistresses premiered on BBC1 on January 8, 2008. Set in a world where friends have become the new family, Katie, Trudi, Siobhan and Jessica are four thirty-something women who met at college and are still good friends, but whose lives have taken very different turns. Each has a different experience of infidelity and love: devoted mistress, wronged wife, unwitting instigator, bed-hopper. Their tangled web of love and deceit envelops all four friends with life-changing results. From dizzy highs to extreme lows, from excitement and happiness to torment and loneliness, the friends are on an emotion fueled journey with no signposts, and are struggling to hold it all together.