The anonymous letter suggesting a respectable factory owner had broken his marriage vows was just the start. Then other letters began arriving, all hinting at misbehavior or worse, each accompanied by a drawing of a rapidly emptying hourglass.

Those receiving the letters all insist the accusations are false, but a suspicious death seems to indicate there may be more than a grain of truth to them. Clock repairer Jacob Silver and his wife Sarah join the police in their Cotswolds market town to discover who wrote the letters, and which one may have revealed a secret worth killing over.