The second Batman/Robin team return, a they face off against the Joker’s son in Batman 145 (Feb. 62), by Finger and Moldoff.
Batman II and Robin II find themselves facing off against the Joker, who has seemingly not aged. And as he is only wearing a bathing suit, his young form is pretty blatant. Oddly, aside from his face, the rest of his skin is not white. The young man introduces himself as the Joker’s son.
Dick and Bruce Jr discuss the situation with Bruce, and the original Batman gets back into costume to go question the Joker. We see the Joker in retirement, tending his garden. He claims to have no knowledge of his successor.
But in fact the original Joker is training the young one. He is not the actual son of the Joker, but is his protegee.
The big finale has the two Batmen and Robin facing off against the Joker and his son. Much better than the previous story. Alfred pops up at the very end, reminding the reader that this is all a story that he is writing.
John Byrne loosely adapts this story in his Generations miniseries.