When working-class student Hannah Ellis (Abra Thompson) goes missing, the police and the public are desperate to find those who might have brought her to harm, but the police soon make an arrest that nobody expected.
Talitha Campbell (Celine Buckens), the daughter of one of Britain’s wealthiest families and a fellow student at Hannah’s university, is arrested in connection to her disappearance.
DI Paula Cassidy (Sinead Keenan), the lead officer on the case, is convinced Talitha had something to do with the missing girl, and Talitha's total lack of empathy for Hannah is only raising Cassidy’s suspicions further.
But before she can charge Talitha with anything, she has to convince the Crown Prosecutor James Thornley (Kerr Logan), who is determined that this case needs to be done by the book, given the keen public interest.
In Talitha’s corner, however, is Cleo Roberts (Tracy Ifeachor) - the duty solicitor on call that night. It falls to Cleo to steer Talitha through her intensive and combative police interviews and evade Cassidy's questions.
As Cleo desperately tries to get Talitha’s attitude under control, new evidence comes to light that changes the nature of the case entirely, and sets the stage for a court case that will divide the nation.
Showtrial begins Sunday 31st October at 9pm on BBC One.