High in the hills above Aberystwyth, the body of an unidentified young man is found at the bottom of a lake in a disused quarry near the village of Penwyllt.
Tommy James, whose business is tractors, lorries and trucks, is a very prominent member of the close-knit community as are his friends; local publican Dic Rees and garage owner Gwilym Morgan. Naturally wary of strangers, the trio offer Mathias no obvious leads, but when the body is revealed to be ex teacher and traveller Michael Reynolds, whom everyone in the village seems to have had an affection for, tongues start to loosen.