Complex sentence: The main theme for the rest of the season is the discovery of ancient relics from Cybertron buried on Earth with the Transformers fighting over each new discovery which ultimately leads their battle all the way back to Cybertron.
Split into simpler sentences: The main theme for the rest of the season is the discovery of ancient relics from Cybertron buried on Earth. The Transformers fight over each new discovery, which ultimately leads their battle all the way back to Cybertron.