Superboy Vol. 1 (1949-1976) / Superboy and the Legion of Super-Heroes (1976-1979) #205

Plot

Superboy and Lana Lang arrive in the 30th century to find Ultra Boy locked up and berserk. After Superboy sets off to retrieve the cure for Ultra Boy's condition, the Legionnaires turn on Lana Lang and prepare to execute her and a rational Ultra Boy. Superboy secretly saves Ultra Boy and Lana Lang from their firing squad, then the three of them destroy the helmet of the alien controlling the other Legionnaires.