Detective Comics #145

ROBIN, THE BOY FAILURE! After a heroic feat, Dick Grayson loses his memory and remembers only the events at Haly's Circus when his parents were killed. Bruce takes him back to Wayne Manor and he tries to make Dick recover his memory by all means necessary. When nothing works, Batman pretends to fall from a building in a similar way the Flying Grayson’s did in the past and Dick's memory finally comes back. THE SMASH-UP HIS HIGHNESS, KING SHORTY UNDERCOVER GANGSTER