Set before WW I, Hugh Frobisher is a reverse remittance man - his wealthy family live in South Africa and he's paid an allowance to return to England. Now he's dead, apparently in a drunken fall from his horse, but an autopsy reveals poison. Suspicion falls on his wife Alice, since they've had quarrels about money, but she's cleared by the evidence of her housekeeper Beth Pottergill. The Frobisher family invite them to live in South Africa - where there's another murder and by poison again. Was the verdict at the inquest wrong? Is Alice a cold blooded murderess? Is Beth protecting Alice - or blackmailing her?