The last time that anyone heard from 35-year-old Claudia Lawrence, a chef at the University of York, was when she sent a text message to a friend on 18 March 2009 at 8.23 p.m. She has never been heard from or seen again, and her disappearance is a mystery that endures to this day. What happened to Claudia that early spring evening - or was it early the following morning on her way to work? There had been nothing abnormal about her behaviour before she vanished, and there were no signs of a struggle at her home. A Crimewatch reconstruction has been broadcast, and the police investigation into the case has cost more than GBP750,000. Dozens of interviews have thrown up numerous leads, but there are no concrete clues. With extensive access to her family and friends, in "Gone", Neil Root assesses the facts and theories and asks: where is Claudia?