Batman and Robin stop a gang of bank robbers. Two are brothers: Mike Grogan and Tommy, his younger brother. Tommy looks up to Mike and has only entered into a life of crime to emulate him. In the end, Mike is killed by another member of the gang, and Tommy aids in capturing the others by calling in the police. As the narration says, Batman and Robin "prove once again to an erring boy that crime does not pay".
Here again Robin is referred to as Batman's "strong right arm".