Star Wars Rebels continues to delight with a Clone Wars throwback episode. 'The Last Battle' pits our heroes against the "roger, roger" chirping Separatist battle droids. These guys were continually trounced by the Jedi, but were oh so cute as they were cut to ribbons. Rex (Dee Bradley Baker) shows a little PTSD as the show addresses the fallout from the infamous Order 66. Palpatine's coup de grace wiped out the Jedi, shut down the droid army, and decommissioned the clones. The Last Battle gives the clones and droids closure, while solidifying the Empire as the real enemy.

The Ghost drops Rex, Ezra (Taylor Gray), Zeb (Steve Blum), Chopper, and Kanan (Freddie Prinze Jr.), at a crashed transport ship on the planet Agamar. Rex believes there will be a huge weapons cache from the Clone Wars. Ezra picks up the head of a battle droid. They laugh as Rex refers to them as 'clankers'. The group finds a trove of proton bombs, but is suddenly trapped by a ray shield. Surrounded by antique battle droids, they are stunned and taken to the command center. Chopper, of course, escapes unnoticed.

Rex wakes up disoriented, calling out Cody's name, his beloved trooper comrade from the Clone Wars. Kanan pleads for him to snap out of it. They are shackled by the droids, and then introduced to their leader, Kalani (Gregg Berger), a tactical battle droid. Rex wonders how they are still operating after all these years. Kalani refused Order 66, believing it to be a Republic ploy. He has been waiting for a final battle to prove the droids superior. He offers them a war game. The Jedi and clone trooper must rescue Zeb from the droids. Ezra, to everyone's surprise agrees, but if they win; they take Zeb and the weapons.

Ezra, Kanan, and Rex are dropped outside the ship. Kanan tells Rex to take command. He has more battlefield experience. They advance into the hangar against the droids. Rex breaks out his Clone War tactics. He orders Kanan and Ezra to block using their lightsabers while he hurls grenades. They get past the first wave of droids. Ezra wants to charge ahead, but Rex holds him back. Kalani has had years to prepare. He's correct. Destroyers rollout above them. Shielded, they bombard them with laser fire. Ezra believes he can get to a crane behind the destroyers. They decide to split up. Kalani, observing the battle, notes that Jedi split up 76% of the time.

Chopper has been hiding. He makes his way to an old shuttle and radio's the Ghost for help. Meanwhile in space, the Ghost is being chased by a fleet of Imperial ships. They were ambushed by Governor Pryce (Mary Elizabeth McGlynn) and Agent Kallus (David Oyelowo). On the Ghost, Hera (Vanessa Marshall) and Sabine (Tiya Sircar) comment that Kanan is on his own if they need help. At that moment, the Imperials intercept Chopper's distress signal. Pryce orders the nearest outpost to investigate.

On Agamar, Ezra runs into Chopper while making his way to the crane. Chopper shows him the shuttles. The delay has trapped Rex and Kanan. Rex is overcome by battlefield shock and races ahead. He's shot, but saved by his Generation One armor. Ezra tells Chopper to prep the shuttle. He uses the force to drop the crane on the destroyers and droids. Rex is livid that Ezra was late to rendezvous. He chides him for lack of discipline. Kanan comforts Ezra, explaining this battle was programmed into Rex. Just as in Kalani's case, the clones were bred for this purpose.

They get closer to the command center, but are again trapped by destroyers. They are able to get past their shields. The destroyers are ancient and malfunctioned. The team fights their way to Kalani. Rex claims victory, but Kalani disagrees. As a droid puts a gun against Zeb's head, Ezra yells for everyone to stop. This battle is pointless. The droids and clones were built to lose. Only one faction won the Clone War, and that was the Empire. Pryce's troops arrive like clockwork.

Kalani notes that he is not programmed to fight the Empire. His enemy was the Republic. He orders his droids to investigate. As they greet the Imperial troops, they are blown to pieces. Ezra's point has been made. Kalani reasons that the Republic has become the Empire. They decide to join forces. Ezra tells them about the shuttles. Kalani says they have no weapons. They will be destroyed by the Imperial walkers. He concocts a new strategy for the Jedi and droids to work together.

In the hangar, the droids roll the proton bombs towards the feet of the walkers. They then fire their lasers at Ezra and Kanan, who deflect the beams into the proton bombs. The explosion cripples the first walker. Everyone races to the shuttles. They lift off under a torrent of gunfire. One shuttle is destroyed, but Kalani escapes, as does the Spectre team. Above Agamar, the two shuttles go their separate ways. Kalani agrees the Clone War is truly over, but that the Rebels have a less than 1% chance to defeat the Empire.

Rex congratulates Ezra for finding common ground. He made peace, something that no one else had been able to achieve during the Clone Wars. Ezra replies with the cold truth, they were all meant to lose. They meet up with the Ghost. Kanan tells Hera that they didn't get any weapons, but found a shuttle to replace the destroyed Phantom.

The Last Battle was a great tie-in to Star Wars: The Clone Wars. Characters and events from that series are integral to the Star Wars Rebels storyline, but this is the first time we've seen Order 66 directly addressed. The droids and clones were the fodder in the Emperor's plan to defeat the Jedi. It's good to see them unite here against the Empire. A rogue tactical droid could be a tremendous ally when needed. I have a feeling that we'll be seeing Kalani again this season.