Complex sentence: With help from Wheelie, they track down the elderly Decepticon, who defected to the Autobots years ago, tired of fighting, and he and Wheelie change sides and join the Autobots.
Split into simpler sentences: With help from Wheelie, they track down the elderly Decepticon, who defected to the Autobots years ago, tired of fighting. He and Wheelie change sides and join the Autobots.