On Cybertron, the Autobots have finally taken control of the four Omega Keys and found the Omega Lock. Just when they are about to reactivate Cybertron, the Decepticons arrive with the three humans, Jack, Miko, and Raf captive. Megatron threaten that if the Autobots do not hand over the Omega Keys, they will kill their human allies by exposing them to Cybertron's atmosphere. The humans were willing to sacrifice their lives for their Autobot friends. Optimus says that they would never sacrifice their human friends to save their own world, and they agree one by one to hand over the Keys after they relinquished their relics.
Bulkhead trades with Knock Out his key inexchange for Miko and Bumbleee trades with Soundwave his key inexchange for Raf, thus leaving Jack the last to be traded. Megatron states that Jack was worth two keys, since he carried the Key to Vector Sigma, so Smokescreen gives up his key as well. Ratchet is contacted by June and then cuts her off to clear the comm lines. Once the Decpticons have all the Keys, they activate the Omega Lock's recontruction beam. Megatron targets an old, destroyed building to show the incredible reconstruction effect the beam produces. The Autobots, humans, and Decepticons gaze upon the newly reconstructed building.
While Optimus tried to reason Megatron in returning the humans to Earth, Megatron stated they are far better where they were currently. Megatron then asks if Starscream has targeted the space bridge where he ordered, to which Starscream replies yes. The space birdge opens on top of the Cybertronians and Megatron aims the beam at the space bridge. The beam traveled to the other side of the space bridge, which leads to Earth. June attempts to contact Jack but watches as the beam is across some place in Jasper. Optimus reveals that the beam would make Earth mechanical to the core, killing all lifeforms in the process.
While Megatron was thinking of renaming his new domain, Optimus, gazing at Jack and Miko's pleas for their world, quickly gets away from being held up by the Vehicons as he gets ahold of the Star Saber and runs towards the Omega Lock. Megatron makes his way to him in a short battle with his Dark Star Saber, but the furious Optimus swiftly cuts his new right arm clean off. He then dodges blasts from the other Decepticons, steps on Starscream's face and slices the Omega Lock, causing a massive explosion. Ratchet comms Optimus and Optimus asks him to open a space bridge. Among the rubble, the Autobots run away through a space bridge with their human allies. Enraged, Starscream wants the Decepticons to follow the Autobots home, but Megatron says they no longer have a home.
Back at the Autobot base, the Autobots are in despair as Bulkhead informs Ratchet about Optimus destroying the Omega Lock. Ratchet is angry at Optimus because he destroyed the only thing capable of repairing their world. The Autobots gather and dicuss the conflict they are in, then they receive a call from Agent Fowler, who tells them to go outside. In the desert outside, there lie a giant Decepticon fortress, the only thing the Omega Lock was able to build before it was destroyed. The Autobots soon realize that the reason the fortress was there was because the Decepticons had discovered the location of their base.
Starscream begins the first wave of attack, which include numerous Fliers and Insecticons. The Autobots, after a short struggle, retreat to the inside of their base, leaving only Agent Fowler driving a helicopter to fight. When Fowler gets cornered, Wheeljack arrives piloting the Jackhammer. Fowler meets with June, who is worried because she had not heard from her son.
Megatron orders the Nemesis to hover directly above the base, where a giant laser cannon is charging. One by one, all of the Autobots, except Optimus who stays to ensure that the Decepticons do not find them, scatter throughout the country through the Ground Bridge. When June and Agent Fowler look at the base, the cannon finishes charging. Optimus takes out the Star Saber to destroy the Groundbridge's controls. As he makes his blow, the Nemesis fires its cannon on the base, creating a devastating explosion and completely destroying the Autobot base. Both June and Agent Fowler watch in horror.
Megatron and Starscream observe the remains of the base, excaiming that Decepticon victory was upon them and the divided Autobots had fall. Through the rubble of the destroyed base, Optimus Prime's arm can be seen, laying motionless within in the fallen debris.
- Optimus Prime
- Knock Out
- Silver Jet Vehicons
- Bombshock (Presumed)
- Jackson Darby
- Miko Nakadai
- Rafeal Esquivel
- William Fowler
- June Darby
- Peter Cullen as Optimus Prime
- Sumalee Montano as Arcee
- Kevin Michael Richardson as Bulkhead
- Jeffrey Combs as Ratchet
- Nolan North as Smokescreen
- James Horan as Wheeljack
- Frank Welker as Megatron
- Steve Blum as Starscream
- Daran Norris as Knock Out
- Josh Keaton as Jackson Darby
- Tania Gunadi as Miko Nakadai
- Andy Pessoa as Rafeal Esquivel
- Ernie Hudson as William Fowler
- Markie Post as June Darby
- The Decepticon fliers get a new paint job. It's not revealed where they got them, but they still look sweet.
- This is the season 2 finale.
- Optimus develops further in this episode, now showing that he is willing to sacrifice even the restoration of Cybertron to save Earth.
- This is the first time that all seven main Autobots have appeared in the same episode.
- The Omega Lock surge would later reveal to lead Ultra Magnus and Shockwave to Earth.
- Megatron got his new right arm severed, a reference to the end Revenge of the Fallen where he lost his right arm. It is possible this was done intentionally because the executive producers are the writers for the live action film movies of Transformers.
- June makes her return in this episode, having not appeared since Orion Pax, Part 3, way back at the beginning of the second season.
- Megatron is able to transform without his right arm.
Main Article: Darkest Hour/Gallery