Countdown to Extinction

Starscream's scheme to harvest energy by detonating part of the Earth threatens to destroy the planet entirely.

The previous threat of Cybertron's orbits over Earth have passed. Optimus Prime and the Autobots work to help repair cities and do other generous/benevolent type things. After all, Megatron is MIA, believed killed in the explosion that moved Cybertron from Earth's orbit. But they are not the only ones affected by Megatron's absence.

With Starscream having gone AWOL and their headquarters still heavily damaged, the Decepticons are in disarray; Skywarp picks a fight with Rumble and Frenzy while Thundercracker fruitlessly tries to keep them on task. This squabbling is short-lived, however, as Megatron returns, having survived the explosion of his starship. When he learns that Starscream and Doctor Arkeville are apparently working together, he sets off in pursuit with the other Decepticons.

Starscream, still believing Megatron destroyed, forces Doctor Arkeville to take him to his secret laboratory. Once there, he discovers another of the Doctor's inventions, the Exponential Generator, a power source that, if it overcharges, will detonate with enough energy to destroy the Earth.

Seeking to gain power for himself, Starscream links the generator to a timer and then takes Doctor Arkeville with him to Cybertron, which is still nearby. He plans to collect the energy unleashed by Earth's destruction to revitalize Cybertron. He coerces Shockwave into serving him, and to help in the restoration of Cybertron.

The Autobots detect the Decepticon activity and set off after them. After a short battle the Autobots are trapped in quicksand. Ironhide freezes the quicksand with his liquid nitrogen allowing them to escape. Laserbeak, who was standing guard over them, is captured and Jazz forces him to play his findings. The Autobots learn that the Decepticons are heading for the Doctor's secret laboratory and they set off to follow them.

The Doctor, unwilling to let Starscream benefit from the Earth's destruction, attempts to sabotage the energy collectors, but the Decepticon security system stuns him with a blast of electricity. Starscream has the badly-injured Doctor 'repaired' by the medicroids, leaving him more machine now than man. Of course, he was twisted and evil to start with, so.

The Autobots and Decepticons arrive at the laboratory and battle each other again. Unaware of the danger it represents, Megatron covets the exponential generator and fights Optimus Prime for its possession. During the fight, Megatron receives a communication from Shockwave on Cybertron.

Shockwave, unwilling to further serve Starscream, warns Megatron about the timer and Starscream's plan. Megatron rips the timer from the wall just in time. On Cybertron, Starscream is baffled that the Earth has not exploded and sets off back to check the timer.

—Rumble and Skywarp shortly before the former gets owned.

— Frenzy and Skywarp bickering before resorting to violence.

—Dr. Arkeville shows Starscream the entrance to his secret lab.

—Jazz and Optimus Prime

—Megatron's interest in the exponential generator gets a little creepy.