A stone circle, showing abnormal energon readings, is activated during a Predacon attack and attracts an alien probe. While investigating it, Optimus is disintegrated, leaving the Maximals bickering over who's in charge, while the Predacons prepare to attack.

After repeated ambushes by the Predacons, this time costing the Maximals a stasis pod, Optimus calls Rattrap's loyalty into question, and sends him off into Predacon territory to look for energon. Once there, he is attacked by Terrorsaur, and offers to surrender... and become a Predacon.