After thoroughly modern Margaret's visits to the vicarage start leaving Mrs Maguire's nose out of joint, Sidney is hoping for a distraction – which arrives in the unexpected form of a young man sat alone in the church and covered in blood. The man is Theo Graham [Jeremy Newmark Jones], and he confesses to Sidney and Geordie that he attacked and killed his landlord, Eric Whittaker [Michael Shaeffer]. But when Sidney and Geordie call on the Boarding House that Eric ran, they find the alleged victim alive and well, along with his teenage daughter Joan [Rosie Day] and her step-mother Vivian [Liz White]. Eric believes Theo is a fantasist. Back at the station, despite his protestations that Eric will come after him, Geordie sends the young man on his way. Hours later, however, witnessed by Sidney and Geordie, Eric is killed in a hit and run.
Sidney comforts Vivian at the hospital, but back at the boarding house he finds her relationship with Joan to be strained – all the more so when Joan learns of her father's death. When Theo arrives to claim his belongings, Sidney ends up chasing him from the boarding house, but the pursuit ends when Theo slashes Sidney with a knife.
As Vivian tends to Sidney's wounds, he becomes drawn deeper and deeper into the twisted emotional world of the boarding house. Who is Vivian trying to protect? What does seemingly shy and single boarder Raymond [John Voce] really want? And how far will Sidney have to go to uncover the killer.
With Leonard distracted by secretive trips to the cinema and Geordie compelled to deal with a surprising shoplifter, who is watching Sidney's back?
