Endgame, Part 1

The Autobots discover Omega Supreme's energy signal on the Moon. Rachet insists on going there right away to save him, but Prime refuses, knowing that they are too weak to fight Megatron. Ratchet, Sari and Professor Sumdac build flight boosters for Optimus to even the chances. Prowl tries to put the Allspark back together, using processor over matter. Meanwhile, Shockwave finally gets Arcee's codes and uses it on protoforms (stolen by Starscream, to make his clones) to duplicate Omega Supreme. Finally, Omega Supreme's clones fly from the Moon to invade the Earth. The episode also shows some of Optimus Prime's memories about being expelled from the Elite Guard and meeting the other main characters.