The Legion of Super-heroes in the 31st Century (2007-2008) #9

“BAD IDEAS.” An ancient legacy catches up with Brainiac 5 when he learns the terrible secret of his great-great-grandfather, Brainiac 1...one of Superman’s greatest enemies! To make it up to him, Brainy takes Superman on a trip to Krypton’s past, but an unexpected detour to the Phantom Zone could mean disaster for the Legion’s future!