The Autobots face the Decepticons for a final showdown.

The Autobots go to the Earth's core to fight for the planet; and Jack uncovers info about Optimus' background.

Bumblebee discovers that MECH and Starscream are responsible for his troubles; Ratchet confronts demons from his Cybertronian past.

Megatron doubts Predacon and its allegiance after Predacon reveals a secret of its own.

Earth has an outbreak of natural disasters, caused by Dark Energon.

Optimus Prime travels to Antarctica to hunt down the second relic, but while there he is confronted by Dreadwing and Starscream, and finds himself caught between shifting alliances.

Ratchet becomes a threat to everyone after he injects himself with an experimental substance.

Optimus begins to piece together his real identity using several clues (including Starscream referring to his as a "prime" -- whoops!), and eventually rebels against Megatron’s orders. Meanwhile, Optimus' Autobot pals hatch a risky plan to get their leader back.

Due to Megatron's crafty plan, Optimus must make a hard decision which could affect the whole Autobot team.

Two patrolling Autobots end up trapped in a cave with their enemies, Starscream and Megatron.

Led by a new member, Team Prime launches a desperate assault on the Decepticon citadel.

The Decepticons and the Terrorcons go into battle against the Autobots.

Ratchet finds himself in a series of predicaments as he resumes his experiments on Synthetic Energon.

Miko and Wheeljack embark on a quest for revenge.

Megatron manipulates the impaired Optimus into joining the Decepticons.

Megatron infuses The Nemesis w/ his own supply of Dark Energon which results in the ship taking on a life of its own with its own agenda. Meanwhile Optimus reluctantly decides to use the Spark Extractor in an attempt to bring the war to an end.

The Autobots and Megatron's Decepticons are drawn into Cybertron to face each other in a heroic battle over their mutual quests for the coveted Omega Lock, which, once unlocked with the four keys, would reawaken Primus'

Megatron controls Bumblebee from inside his mind and influences his behavior at HQ.

While Optimus faces off with Predaking, Megatron mounts a campaign to form a new alliance.

Following from the events of the previous episode, Agent Fowler is sat down to explain recent events to his superior, the cynical and disbelieving General Bryce. Threatened with a military tribunal and Team Prime's termination, Fowler tries to convince the General that the Autobots are still on the military's side, but the General believes that Optimus Prime went rogue and has perished, failing to fully understand that Nemesis Prime was not the real Optimus.

The kids are stranded with Skyquake in an alternate dimension during a GroundBridge malfunction.

Jack tries to be impressive, with Bumblebee's help, but Knockout's arrivals sends things out of control.

Bulkhead is unknowingly shadowed by Miko as he goes to rescue Agent Fowler, who was kidnapped by the Decepticons.

The Autobots try to claim a magnetic weapon before the Decepticons get to it.

After being granted a new start in his life, the ever stone-faced Silas begins to see the world in a new light and makes an out-of-character decision to go to Megatron in the hopes that he will be allowed to join the ranks of Decepticon.

In an effort to secure a peaceful truce that would be beneficial to all parties involved, Starscream offers Megatron a ceasefire but Dreadwing has other ideas and does whatever he can to keep the diplomatic agreement from taking place.

When the Decepticons take him captive, Smokescreen learns of the location of the final Omega Key - and attempts to retrieve all of the other stolen keys from Megatron.

Starscream pursues other interests while Skyquake battles with Optimus Prime and Bumblebee.

Megatron goes on a conquest to reveal the rest of the relics while Arcee and Bumblebee race him to New York City before Megatron gets there.

MECH agents capture a Decepticon, and the Autobots mount a rescue.

The Autobots go in search of Cliffjumper, whose life signal is weak and find Megatron wielding the dangerous dark Energon.

Miko and Bulkhead go up against Starscream and Breakdown as they go to Greece to retrieve an Energon Harvester.

Arcee must protect Jack when a routine mission is complicated by Airachnid's arrival.

Scraplets invade HQ while Optimus and Arcee patrol the Arctic, leaving Bumblee and Ratchet to repel the enemy.

As the race for the Omega Keys grows more desperate, Knock Out harnesses the power of sound, and Starscream the power of hyper-speed.

The Autobots are attacked while helping Agent Fowler transport an implosion device.

Bulkhead acquires a top-secret formula, and the Decepticons come after him for it.

The Decepticons quickly try to build a space bridge before a prophesied darkness arrives.