6/6. A cryptic late night call from Holly sees Lucy lured into danger. Back at the station, all eyes are on John as the pressure ramps up. Will his cover finally be blown? Also in HD. [S,AD]
5/6. John and the gang go back to school to investigate the suspicious death of a headmaster. Lucy sneaks off on a covert mission, and a shocking revelation leaves John reeling. Also in HD. [S,AD]
3/6. A new case takes Ludwig on a walking tour of Cambridge, where he's faced with a conundrum. Meanwhile, Lucy goes undercover and makes a grim discovery of her own. Also in HD. [S,AD]
2/6. On a mission to crack the code in his twin's notebook, John returns to the police station. A frustrated Lucy takes matters into her own hands and plays detective herself. Also in HD. [S,AD]
1/6. Puzzle setter John 'Ludwig' Taylor's life is upended when his identical twin, DCI James Taylor, disappears. John reluctantly assumes his identity in order to track him down. Also in HD. [S,AD]