Sian O'Callaghan goes missing after a Friday night out in Swindon Old Town. As the family desperately waits for news, the police search for any clues to where she could be.
A confession follows police officer Steve Fulcher, played by Martin Freeman, who is the leading officer in charge of the case on missing girl Sian. A confession looks at the many lives affected by the disappearance including two families and the police themselves.