At the edge of a lake in a small New England town, two men are busy digging a trench for a waterpipe on the land recently sold to a businessman by an elderly local woman, Emily Bristow, when they discover human remains, and a necklace lying in the place where the skeleton's neck should be. They go to the town's district attorney, Andrew Warren, who asks them to leave it with him. He recognises the necklace, since it was he who had presented it to Emily Bristow on her 24th birthday, over 40 years ago...