Final Crisis: Legion of Three Worlds #5

Synopsis

While Superboy leads the charge against Superboy-Prime in the 31st century, Superman and the Legion founders fight the Time Trapper at the end of time. Tapping into the unique properties at the end of time, the founders bring in Legionnaires from many different timelines and alternate realities to help them. As the tide turns against the Legion of Super-Villains in the 31st century, the founders and Superman bring the Time Trapper there, where Superboy-Prime, enraged at the Time Trapper's claim to be his future self, knocks the Trapper out of existence, which sends Prime back to his old life.