He went on many adventures with Batman. One night, Robin thought that he was saving an innocent woman from evil thugs, but it was just a trap set by the Joker and the woman was Harley Quinn in disguise, who then knocked out Tim. The Joker then tortured him for days at the old abandoned Arkham Asylum. He learned what Batman's secret identity was from him and then he "made" him into a "son" - Joker Junior. Then Joker tried to use him to kill Batman, but Tim turned and killed Joker instead with Joker's BANG! flag gun. Luckily, Dr. Leslie Thompkins, a close friend of the Wayne family, managed to restore Tim to normal. However, from that point on, Bruce forbade Tim to ever work as his partner again.