The Legionnaires are asked to guard three very important towers to defend against an alien invasion, but it seems a traitor on the team is destroying the towers. All things point to Karate Kid, one of the newer members of the team. The seasoned members join up and go to confront Karate Kid to accuse him. Surprisingly, the find out that it was Nemesis Kid who betrayed them. The Legion of Super-Heroes defeat the alien invasion but Nemesis Kid teleports away when confronted by so many powerful beings.