When Tygra mysteriously vanishes, taking the Eye of Thundera with him, Lion-0 and the rest of the ThunderCats thrown into turmoil. But things really get confused when Tygra reappears as an old man! He claims to have been sent into the past through a mishap with a time door, and forced to survive in isolation on Third Earth until he caught up to the present day. But the old Tygra seems changed in more fundamental ways than his age -- and those changes are definitely not for the better!