A young girl is bored and Googles her name. Weirdly, she finds another Jessica, same age, also living in London. They arrange to meet. At the designated time, designated place, Jessica sees the girl she is supposed to be meeting, shock registering on both their faces as they realise they look identical. They shake hands, and at that moment are catapulted into each other's worlds. Jessica finds herself somewhere which looks like the London of 50 years ago, but the year is still 2008 . . . In the parallel London, the history is different - key war memorials are missing, and the Jessica who's life she now inhabits was involved in a dark and sinister conspiracy. Jess must convince everyone she is the same girl, at all costs - if she wants to get back to her London - alive.