Darius left prison with two secrets. He was the only person who knew where the loot from his last jewelry robbery was hidden. That--if he could recover it undetected--would take care of his financial problems for the rest of his life. Even Darius was unaware of his second secret, at first. He didn't know that the radiological experiments for which he'd volunteered had left him a changed man. Someone had failed to remove a particle of material which had been imbedded in his body. When the hands on his new watch reached the right position, Darius, the Mr. Hyde of jewel thieves, became a sexual Dr. Jekyll!