Elizabeth Best retired from MI5, and her former husband Douglas Middlemiss is still in the secret service. He is part of an operation at a criminal banker’s house, where a bag containing £20 million in diamonds has gone missing. Everyone suspects him, and several people want those diamonds to themselves. One of them kills Douglas, but the clues to the whereabouts of the diamonds are too cryptic for anyone except Elizabeth and her three chums to solve.
Meanwhile, Ibrahim is mugged by a young hood and left for dead. He recovers, but the police can do little to bring the perpetrator to justice. The crew are left to exact revenge with the hood themselves.
A fast paced, cleverly written mystery novel, with witty dialogues and amusing situations, despite the summary sounding rather grim. The eventual culprit may have been obvious, but the steps the quartet take to identify and collar them is excellent reading.