When John ‘Ludwig’ Taylor’s (David Mitchell) identical twin, DCI James Taylor, disappears off the face of the earth, John takes over his brother’s identity in a quest to discover his whereabouts. John has never married; never had a family and never really ventured further than his own front door. Without a computer, mobile phone or even a television, he lives in quiet solitude, designing puzzles for a living, under the nom-de-plume of ‘Ludwig’. This genre bending detective series follows full-time luddite, John 'Ludwig' Taylor, as he assumes the identity of his missing twin brother in a bid to track him down and bring him home. However, filling the shoes of your identical twin is one thing - when your twin also happens to be a successful DCI leading Cambridge’s busy inner-city major crimes team the stakes are much higher. John may be a master of all things cryptic, but can he crack the biggest puzzle of his life?