Dick Halstead, a jewelry salesman, is sent to deliver a necklace worth $6,200 to a Mrs. Collingwood, a neighbor of his friends, the Barrys. Tom Barry and his young wife invite Dick to spend a night at their house. As he had to deliver the necklace to his wealthy patron the following day, he accepts. He shows the necklace to Tom and Pearl and they are fascinated by its beauty. They lock it in their safe, the combination of which is known only to Tom and his wife. They retire. Mrs. Barry, addicted to the sleep walking habit, although this was unknown to her husband, gets up in the middle of the night, opens the safe, takes out the jewels, and re-locks the safe. She then wanders around the house and finally goes out into the garden, where she hides the necklace in the hollow trunk of an old tree. She returns to bed. The next morning they come down to breakfast and Dick, being ready to leave, they all go upstairs and Tom opens the safe. To their consternation they find the jewels gone. Dick, nearly frantic with despair, does not know what to do, and Tom and his wife are at a loss to know how to account for the mysterious disappearance, inasmuch as they were the only two who knew the combination to the safe. The strange part of it all was that no other article of value in the safe had been touched. Tom insists that he is responsible to Dick for the loss, as it happened in his house, and immediately mortgages his home to make good Dick's loss, and thus saving his position. Mrs. Barry is nearly heartbroken, and when the detectives gave up all hope of ever finding the thief her sorrows were enhanced. A year passed and during that interval almost every night Mrs. Barry, working under the influences of the subconscious mind, was wont to arise and go to the hiding-place of the jewels and try them on. The mortgage on the home is due and is about to be fore-closed for non-payment, when one night Pearl being ill, Tom goes out to get some medicine for her. She falls asleep and as usual goes out and gets the necklace. When he returns she is holding it in her hand, though it can be seen that she is fast asleep. He cries out in his astonishment and accuses her of being a thief, but only succeeds in awaking her, and then realizing that she had done all this in her sleep, he takes her in his arms and readily forgives her failing, as her finding the necklace enabled them to place Dick absolutely right with his firm, and their money being returned to them, the mortgage was not foreclosed and their home saved.