"The Legion of Super-Executioners":
After celebrating her birthday with family and friends, Lana is pleased when Superboy finally shows up to give her his gift, which is a trip to the 30th century
When they arrive at Legion headquarters, they're told the team is in the midst of a crisis. Ultra Boy has had fits of madness, tearing up the place with his increased super-strength. The Teen of Steel goes into Jo Nah's containment cell, in hopes of finding out what's wrong. But even the Caped Kryptonian is no match for the hero from Rimbor, who uses Superboy's own cape to tie him down and render him unconscious.
Brainy theorizes that a virus is causing the psychosis and that waters from a twin-ring planet should cure Ultra Boy. Superboy flies off to get the water. But it's a wild goose chase, as in reality it's the rest of the Legion that have gone crazy and Jo Nah is the only sane one.
Lana and Jo are put in front of a firing squad and left for dead, while the Legionnaires depart to work on their project for the "Master."
In fact, the Teen of Tomorrow saved the two. Ultra Boy had tied Superboy's cape in a Hoax Knot, which suggested there was something phony going on. Lana switches to her Insect Queen identity and the three find the Master overseeing the project--a space arc!
Using his control helmet, the Master commands Insect Queen to sting Ultra Boy. He then tells Superboy his plan--to take the Legionnaires to another planet and breed them until he's built up an army of super-beings.
However, Lana's sting was not deadly and Ultra Boy removes the Master's control helmet, ending the threat.