The Riddler is back in Batman 279 (Sept. 76), and Robin is around for this Reed, Chan and Blaisdel story as well.
It’s a serviceable story, but not a really stand out one. Batman and Robin race around, following the Riddler’s clues, but always one step behind. Notably, the story opens with the Riddler escaping from a prison, not from Arkham Asylum.
The cover combines two different scenes in the story. Batman and Robin face off against a pair of Riddlers at one point, though neither is the real bad guy.
The mummy case appears in the final scene, as Batman figures out that the “riddle without an answer” is a reference to the Sphinx, and that the Riddler’s goal is a golden version at a museum. The story ends as Robin gets to do a knock knock joke at the Riddler’s expense.