When the Midsomer canal tunnel collapses during a restoration project, DCI Barnaby is tasked with identifying the skeletal remains that may have been bricked up inside a wall for decades. Meanwhile, Sergeant Troy is promoted to Inspector, but his celebrations are short lived when he's called out to Midsomer Worthy where a local homeless man has been attacked by a gang of youths.

DCI Barnaby and Sgt Scott find themselves investigating the bizarre murder of a young, wealthy landowner, Gareth Heldman, whose body turns up with an unusual stab wound to the thigh.