Years ago, following their encounter with Sixshot and Metroplex on the planet Salvvatan VIII, the surviving Throttlebots—Goldbug, Chase, Rollbar, and Searchlight—were attempting to depart in the shuttle Metroplex provided them when Sixshot struck back. Though the Throttlebots believe they were able to kill the already-wounded Sixshot in the ensuing battle, he succeeded in crippling their shuttle, and they crashed on a strange plant-world that Searchlight eventually named "Botanica." Attempts to radio for assistance met with failure; the Decepticon uprising known as the Surge was in full effect across the galaxy, sweeping over all Autobot installations and cutting the Throttlebots off from any potential rescue. Left to believe the Autobots had lost the war and that one day the Decepticons would arrive to kill them all, the four have eked out a meager existence on the planet ever since. That all ends today... on the day the attack they have long been expecting finally comes, not from the skies above, but from below, as monstrous animal-form Transformers emerge from within the planet!

On Cybertron, in the wake of Joe Colton's attack on the planet, Optimus Prime presides over Sideswipe's delayed funeral. Afterward, he and Sunstreaker make peace; the recent chaos has led Sunstreaker to understand why Prime could not be there when Sideswipe died. Prime turns introspective, made aware once more of how much suffering those under his command have been through as an indirect consequence of the things he asks of them—yet they remain willing to do those things all the same. He attempts to vocalize these emotions to Arcee and thank her for her service, but she blindsides him with the revelation that Galvatron was her twin brother—a brother she stood by and let Optimus kill, because, once again, it was the "right" thing he had to do. Disarmed by this, and unsettled by the growing crowd of admirers who have come to watch him, Prime attempts to withdraw, but finds his way barred by Garrison Blackrock, who has some troubling news of his own to share. Blackrock explains the half-human/half-Cybertronian Centurion has been reawakened from stasis lock by the recent planetary energy surge caused by the alien wizard Merklynn, and has since disappeared into the wilderness outside Iacon. But Blackrock has just received a transmission from Centurion containing the image of a protoform—something that, to Prime and Arcee's knowledge, has not existed on Cybertron for millions of years. Overhearing their conversation, repentant Decepticon Swift corrects them: she and the Dinobots recently discovered an active hot spot from which such a protoform could have emerged... a hot spot that subsequently vanished, but which Starscream also knows about.

Prime and Blackrock approach Starscream to discuss the matter just as he is getting out of a meeting with the Council of Worlds, during which tempers have flared over the fact Cybertron has suddenly found itself reliant on Earth to provide it with energon, after Merklynn's schemes have left the planet's own fuel supply tainted and unusable. Starscream takes Prime to former Dinobot leader Slug, who has been convalescing in his care after recent injuries, and who agrees to help track down the Dinobots and the protoforms—though none but Starscream are aware that Slug was not merely injured, but killed on Starscream's orders by Sandstorm, then reanimated by Starscream using technology acquired from the captured Bludgeon...

Arcee approaches Pyra Magna, Stormclash, and Skyburst in the middle of the battle-blasted plaza that was ground zero for Colton's attack, inviting them to join the mission into the wilderness. The group politely turn down the offer, their combiner physiology necessitating that they soon return to Earth to be close with their sister Torchbearers again—but the subject of combiners allows Pyra to switch the topic to Prowl, and the need for more robots like him who are willing to act as a check and bala

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