On the enigmatic planet of Cybertron, a world teeming with Energon-powered sentient robots, one particularly curious robot named Orion Pax decides to sneak away to watch a documentary made by the original inhabitants of Cybertron. However, his aspirations lead to trouble as he gets apprehended by the security bots and sent to prison. Fortunately, his loyal friend D-16 orchestrates a daring rescue. As they return to their subterranean workspace, they inadvertently trap another miner, Jazz, while their leader, Elita-1, bears the brunt of the blame and faces demotion.

In the meantime, Cybertron’s leader, Sentinel Prime, returns victoriously from an expedition on the planet’s surface, claiming to have repelled the invading Quintesson aliens. To celebrate this feat, he organizes a thrilling race. Orion and D-16, eager to prove themselves worthy beyond their roles as miners, enter the contest sporting improvised jet packs but ultimately come up short. Despite their loss, Sentinel Prime plans to reward them, but their escapade takes a turn for the worse as they find themselves caught once again and relegated to the duties of garbage disposal and incineration.

While dealing with their dreary tasks, the pair encounters B-127, which leads them to discover a distress chip entwined in the refuse from one of the Prime’s calls for help, linked to Alpha Trion. Orion urges D-16, B-127, and Elita to join him in a quest to track down this signal, and Elita decides to join after witnessing them hitch a ride on a train.

Their journey takes them to the surface, where they stumble upon a cave housing the deactivated body of Alpha Trion among the remains of fallen primes. After successfully reviving him, Trion reveals a shocking betrayal; Sentinel Prime has been colluding with the Quintessons, supplying them with Energon in exchange for his dominion over Cybertron. It becomes evident that he has been sabotaging the miners by removing their cogs. Trion bestows cogs and a chip containing evidence of Sentinel’s treachery, preparing them for their mission. However, their celebration is cut short when Sentinel’s forces arrive, capturing and deactivating Trion.

Determined to unveil the truth, Orion and the others set out to return to Lacon but are intercepted by the High Guard. In the midst of chaos, warbots, led by Starscream, rebel against Sentinel. D-16 displays remarkable bravery by defeating Starscream, but Orion grows increasingly concerned about his friend’s darkening demeanor after absorbing the weight of the truth regarding Sentinel. A brutal battle ensues, during which the evidence chip is destroyed, leading to D-16, B-127, and half the High Guard being captured by Sentinel’s troops.

With determination surging, Elita rallies Orion to unite the remaining High Guard and their allies to reclaim Lacon. In a display of leadership, she broadcasts her memory recordings, subduing Sentinel’s lieutenant and igniting hope among the citizens to rise against Sentinel. They manage to confront him, but a grave disagreement arises between Orion and D-16 about the fate of Sentinel, culminating in D-16 accidentally shooting Orion in a tragic altercation. As Orion collapses, witnessing his friend fall, D-16 embraces the name “Megatron” and takes vengeance by killing Sentinel, insisting that the High Guard lay waste to Lacon.

In a twist of fate, the spirits of Primus and the Primes grant Orion the “Matrix of Power,” reviving him and imparting a new name—“Optimus Prime.” Armed with the newfound power, Optimus confronts Megatron and the High Guard, ultimately overcoming them and exiling the traitorous duo. The Matrix breathes life back into Cybertron’s desiccated Energon rivers and restores the miners’ cogs. Finally, Optimus anoints his followers as Autobots, sending a stern warning to the Quintessons to keep their distance from Cybertron. Meanwhile, Megatron, having renamed the High Guard to the Decepticons, plots an ominous return to challenge Optimus Prime once again.