S8·E4 The Case of the Shrinking Super Friends / The Mask of Mystery

The Case of the Shrinking Super Friends: Lex Luthor invents a shrinking ray and uses it on the Hall of Justice. The older members of the Justice League had earlier flown off to fight a mission in space... leaving behind the junior members like Robin, The Wonder Twins and Gleek, and Firestorm. Luthor succeeds in shrinking the Hall of Justice and it's up to the now miniature Super Friends to save the day before the senior members of the group return from space.

The Mask of Mystery: Lex Luthor uses a clumsy fan of the Super Friends to destroy them. The fan Sidney Wanamaker, a school mate of Firestorm's alter-ego, Ronald Raymond, creates his own secret identity... called Captain Mystery. He taps into the Hall of Justice files and shows up to help the Super Friends but winds up causing more harm than good. Luthor notices this and kidnaps Captain Mystery and intends on using him in his plot. It's up to the Super Friends to rescue Captain Mystery and capture Lex Luthor.