Joanna Lumley joins the cast of the drama about four women whose lives have all been touched by infidelity. Katie's mother has come back into her life, and is concerned about her daughter's destructive romances. Trudi's business is putting her relationship with Richard under intense pressure, Jessica pines for a baby and Siobhan's contentment with the single life comes to an abrupt end when her daughter's father reappears. Sarah Parish, Sharon Small, Shelley Conn and Orla Brady star