Two years have passed and the once-unbreakable bond between best friends Katie, Trudi, Jessica and Siobhan has been shattered. As the girls gather it's clear their relationship has changed dramatically: there's tension in the room and no happy greetings. What could have happened to bring them to this?

Katie is forced to take a trip down memory lane as she visits the house she grew up in when her interfering mother, Vivienne, unexpectedly announces that she's planning to sell the property. But Katie finds more than she bargained for and unearths a disturbing secret that threatens to destroy her fond childhood memories.

The tension mounts as Mistresses concludes.

Trudi, Jessica, Katie and Siobhan are united in grief following the death of a loved one. However, emotions run high at the funeral and, with so many questions left unanswered, grief turns to anger and a bitter row ensues, causing a huge rift between the friends.