Transformers: Prime/Recap/S1/E25 One Shall Rise Part 2

Optimus Prime is battling a small army of Unicrons made from mountain rocks. Team Prime wishes to back him up, but Optimus belays the order, for as Prime, he is the one Unicron is after. Team Prime, against his orders, decide to reinforce him anyway, and Arcee, Bumblebee, and Bulkhead arrive to the area by Ground Bridge. Optimus is angry that they disobeyed him, but Arcee reminds him that since he is Unicron's target, he should retreat back to base. Optimus tells them that Unicron can find him anywhere, so even if he hid at the base, it would only be a matter of time before the Chaos Bringer located him. Bulkhead then asks him to let them take the lead, which he allows after Ratchet's insistence. They fight the stone simulacra until a giant Unicron rises from the ground and comes close to killing Optimus, only to be felled when several blasts knock its head off. Megatron reveals himself to have fired those shots.

After Optimus and Megatron engage in their usual arch nemesis banter, Megatron reveals the reason he's there: He wants to team up with the Autobots to destroy Unicron. The Autobots question this truce, but Megatron assures them that he is the only one who can lead them to Unicron and that Optimus, the last Prime, is the only one who can defeat him. Optimus deduces that since Unicron is at the centre of the planet, they will have to Ground Bridge to the Earth's core, much to Ratchet's dismay. This also means that they will need to Ground Bridge Megatron to the base.

Back on the Nemesis, Airachnid tells Soundwave that it Megatron's protracted absence indicates he has abandoned them, and that they should begin looking at a future without him.

Listening back at base, Jack wonders if they can't just transport Unicron out of the core, but Raf and Ratchet tell him that he is the Earth's core, so any such act could bring the destruction they're trying to avoid. Optimus agrees and believes that the only way to destroy Unicron is for him to unleash the full power of the Matrix of Leadership onto Unicron's spark. Ratchet explains to Fowler and Jack that the Matrix is the combined power of all the Primes and that it exists within Optimus Prime himself.

Before they can discuss any further, another giant Unicron rises from the ground. Optimus calls for a Ground Bridge, and Megatron stays behind to distract Unicron while the Autobots go back to their headquarters. They argue about the details of Megatron coming to base and finally decide to bridge him there. Jack wonders what will happen to Optimus when he unleashes the power of the Matrix; Optimus does not give him a direct answer, but tells them that he is willing to do what is needed and that the rest of the Autobots will carry on. Optimus then calls in Megatron, and the Decepticon finishes off Unicron's rock giant and transports to the Autobot base. After Megatron banters with the Autobots and the humans, everything is set for them to leave. But before they go, Optimus meets privately with Jack to express how impressed he is with how much Jack has grown since they first met. Optimus entrusts him with the key that he claims controls the Ground Bridge operations until he returns.

Team Prime and Megatron leave for the core, arriving in a cavernous interior with crisscrossing constructs. Arcee wonders how long it will be before Unicron discovers them. Megatron tells her that he already knows. Unbeknownst to them, a giant optic watches overhead.

To Be Concluded...

Tropes:

 * Beware the Quiet Ones: You got that one right, Knock Out.
 * Big Damn Heroes: Played straight at the beginning by Team Prime.
 * Big No: Arcee yells out this when Unicron was about to step on Optimus.
 * Enemy Mine: Megatron makes an alliance with Optimus and the Autobots to defeat Unicron
 * Eyes Do Not Belong There: There's one inside Unicron's spark chamber.
 * Villainous Rescue: Megatron rescues Optimus from Unicron.
 * Zerg Rush