Dennis and Rosa are pulled into a dangerous night at The Tavern when Eddie and Tiff agree to a secret lock-in for a gang of hard men led by crime boss Stan Grainger, the villain Dennis once helped send down. Stan recognises him but plays along, turning the boozy party into a slow-burn threat as the men drink and taunt their host. A blackout, a scream and a body on the floor leave the doors bolted and Dennis forced to unpick what happened before the police break in.