Justice League Action - Season 1 Episode 18 Field Trip
Overview: As Superman gives Blue Beetle, Firestorm, and Stargirl a tour of the Fortress of Solitude, they run afoul with General Zod, Faora, and an unidentified Kryptonian villain who are accidentally freed from the Phantom Zone. Now with Superman trapped inside, the three teen heroes must work together to stop the Kryptonian villains.