Cath Hardacre (Whittaker) is a good nurse. Caring and hard-working, she does her best for everyone in the cardiology ward she works on. However, when she raises her concerns about the standards slipping at the hospital her world takes a turn for the worse.
After being sacked for whistle-blowing, Cath turns to her best friend Dr. Ally Sutton, who is leaving her life as an A&E doctor and emigrating to New Zealand with her new husband.
At a drunken party Cath finds Ally’s discarded paperwork and makes the desperate decision to take a second chance at life – by stealing her best friend’s identity.
Cath, now calling herself Ally, accepts a job at a failing emergency department in Edinburgh and embarks upon a new life with her young daughter Molly.
However, with her good-for-nothing ex-partner Karl trying to spend time with them and a journalist chasing her about the issues at her former hospital, how will Ally cope with leading a double life?
Whittaker is joined by Emun Elliott and former Inbetweeners star Blake Harrison.
Trust Me begins on Tuesday 8 August on BBC One.