Plaintiff advertised his car for sale. Roberts stopped by to look at it. He took it for a short test drive, returned to Plaintiff’s house, and said, “I like it, but my wife needs to look at it before I buy it. I’ll be back in less than half an hour.” Roberts takes the car and never returns. Plaintiff called the police, who later found the car in a neighboring state. Defendant had bought it from Roberts, who had presented him with forged registration papers. Plaintiff sued Defendant to get the car back. Who wins? Why?