Carnage in C-Minor

On a musical alien world, Galvatron hatches a plot that hinges on the planet's strange sonic powers.

The Decepticons are building engines into the side of a comet in order to alter its course and crash it on top of Metroplex. As they fire up the engines, a group of Autobots close in, led there by Perceptor. The Autobots attack, much to Galvatron's dismay. The Constructicons form Devastator, who is promptly flattened when Broadside drops on him in ship mode. In the ensuing battle, the engines are destroyed, and the comet is sent hurtling towards a small planet, which Perceptor reports is inhabited.

The Autobots attempt unsuccessfully to stop the comet before Galvatron again orders his men to engage their foe. While Galvatron and Ultra Magnus are grappling, waves of sound energy destroy the comet and cause both groups of Transformers to plummet to the planet's surface. In a nearby city, three aliens are having a disagreement. One of them, Allegra, storms out, saying that she's going to her retreat.

The Transformers recover from their crash, wondering what hit them. Soundwave describes it as the most perfect harmony ever, but Galvatron is more interested in its destructive power. Broadside breaks up the discussion by punching Galvatron, and the fight resumes. As the Constructicons form Devastator again, Perceptor blows the giant apart with one shot from his cannon. Galvatron and Soundwave depart in search of the source of the harmony they heard earlier, but Ultra Magnus spots them leaving and takes Broadside and Blaster in pursuit. Perceptor reflects that unless the trio are swift, there might not be much of them left.

Broadside swiftly passes the two Decepticons and overflies the city, which Blaster realises is laid out like a musical harmony. Magnus and Blaster meet with Basso Profundo, leader of the planet Eurythma, but Basso refuses to help them, believing that the harmony is all his people need to protect themselves. He drops a hint that Allegra might be able to help them, a fact overheard by Galvatron and Soundwave, who are spying outside. As the three Autobots go in search of Allegra, the Decepticons drop a bridge on them. To make sure, Galvatron blasts the wreckage, and the pair fly off to find Allegra.

Basso watches the two Decepticons leave, and fellow Eurythman Zebop Skandana uses a harmony to help the Autobots out of the rubble. Blaster realises that Zebop was creating part of the harmony which originally blew the Autobots out of space, and Zebop says he's sympathetic to their cause and will help them find Allegra.

The two Decepticons meet Allegra, offering to help her overthrow Basso in return for the secret of the harmony. She obliges and Soundwave records it, but to Galvatron's rage, it turns out that she is only one part of the harmony; Basso and Zebop make up the other two thirds. Still, when the Autobots arrive with Zebop, Soundwave is testing the part of the harmony he has by destroying a rock. The Autobots set up an ambush, but Zebop is so distressed by the fact that Allegra is working with the Decepticons that he gives away their position. Galvatron starts firing, and Zebop takes refuge in Ultra Magnus's cab. Soundwave begins battering the Autobots with the harmony. When Zebop counters with his part of the harmony, Soundwave promptly records it and uses the resulting two-thirds of the harmony to devastating effect.

With the Autobots apparently gone, Galvatron terminates the alliance with Allegra. She attempts to attack them with her part of the harmony, but Soundwave retaliates, knocking her out. The Autobots climb out of their hole in time to prevent Galvatron from terminating the Eurythman, but during the resulting fight, Blaster and Soundwave struggle and accidentally fall on Zebop. Galvatron grabs his minion and departs, leaving Allegra cradling Zebop in her arms. Though the Autobots believe he's had it, Allegra uses a harmony to revive him. The Autobots leave for the city.

Back at the landing site, the rest of the Autobots and Decepticons are still fighting. Hot Spot voices his hope that Magnus, Blaster and Broadside hurry. The Eurythmans have spotted the battle, and Basso uses an amplifier to direct a destructive harmony at it. Defensor is forced to disassemble, but the two factions fight on. Basso is depressed, and his aide points out he needs Allegra and Zebop to complete the harmony. Arriving, Soundwave begins playing two-thirds of the harmony, shaking the city and provoking Basso into using the third part again, which Soundwave promptly records. He is subsequently able to use the complete harmonic weapon to attack the city. Pleased, Galvatron announces their next targets are Metroplex and then Cybertron.

—Galvatron and Soundwave wonder what hit them, to the latter's monotoned enjoyment.

—Broadside, right before he sucker-punches Galvatron

—Ultra Magnus, who doesn't have any soul, and Blaster, who does.

—Broadside and Blaster get their vibes harshed.

—Blaster destroys Soundwave's tapes, to the Decepticon's monotoned horror.