Unhappily married to Sir Robert Grimwood, an older man whose only passion is chess, Lady Marion finds solace in the arrival of her old suitor, John Heritage. Soon after Heritage's departure, Sir Robert's body is found floating in the lake. Subsequently, a suicide note is delivered to Lady Marion, charging that her husband's death was caused by Marion's love for Heritage. Lord Waverly, the owner of an adjacent estate, orders his servant Ling Foo to steal the letter, and then demands that Marion meet him or he will expose the scandal behind her husband's death. Arriving at the appointed rendezvous, Marion is assaulted by Waverly. Heritage comes to her rescue and Waverly, in a dazed state, falls to his death over a cliff. Through a series of deductions, Heritage discovers that the bizarre deaths were caused by Ling Foo who years earlier had sworn revenge on Sir Robert for the death of his son.