It is the first arc of the reign of Optimus Prime as leader of the Autobots... and things are not going that well. With plasma pumped from Cybertron's core shot upwards through the city, Iacon disintegrates in flame and molten metal. Both Shockwave and Prowl order their respective armies to evacuate from the carnage. Optimus, armed with a weapon and advice from Grimlock, hunts Megatron. An attempt at an ambush fails, and Prime has the upper-hand against his rival, powered by a new resolve. Within the tunnels, Soundwave finds Megatron, who has a few gaps in his memory. 'Til all are one.