Arcee must protect Jack when a routine mission is complicated by Airachnid's arrival.

Airachnid makes a deal with Silas to get revenge against Arcee and Jack.

The Autobots try to claim a magnetic weapon before the Decepticons get to it.

Starscream makes an unexpected request after he is captured by Optimus.

The Decepticons quickly try to build a space bridge before a prophesied darkness arrives.

Earth has an outbreak of natural disasters, caused by Dark Energon.

The Autobots acquire a surprising ally in their battle to save Earth.

The Autobots go to the Earth's core to fight for the planet; and Jack uncovers info about Optimus' background.