A savage and macabre murder occurs in East Anglia, on the edge of the Wash. Superindendent Kenworthy, John Buxton Hilton's eccentric and ingenious policeman, faces the task of unravelling the past of the Margerum family who are rooted in the Fens and evidently connected with the murder.

It is in the past history of this large and complicated family, and in a strange and touching romance that took place in the 1920's, that the secret motivations lie. Kenworthy is perfectly contented to employ ruthless bluff and downright lies to bring pressure that will break the case open. His winger, Detective Sergeant Wright, has the curious role of having to make what he can of it all, building to an ending with a cunning surprise.

This splendid story gains its strength from the evocation of the coastal marshes, the character and manoeuvres of Kenworthy and in a strange tale of love recalled from the past.