When Edwin Garland dies of a heart attack, no one outside the expectant circle of his relatives is concerned, but the situation changes dramatically when, on the evening of the funeral, his son is shot dead. Chief Superintendent Wycliffe is faced with a seemingly motiveless killing, and Edwin's will, though mischievously contrived, offers no explanation.
Garland had been friends with Gifford Tate, a well-known painter who died several years before. Now, the only clue Wycliffe has to the murder is an artists' pigment called Winsor Blue. He finally identifies the motive behind the crimes - but is it too late to prevent another death?