Metroid Prime

Long ago, a bird-like race of creatures called the Chozo became extremely advanced technologically, but due to increasing violence in the universe, they began to hide and live more simple lives. The planet Tallon IV was the site of one of their colonies. Years later, a meteor crashed on Tallon IV releasing the strange element Phazon into the planet. Phazon poisoned anything it came in contact with, causing the plant and animal life to either die or mutate into a hideous form.

The Chozo tried to control the power of Phazon but failed. Before abandoning the planet, they were able to cover the impact crater with a temple and seal Phazon into the planet's core. Now space pirates have discovered Tallon IV, moving in to study Phazon and harnessing its power. They have also begun rebuilding their fortress on planet Zebes and reviving the Mother Brain, Ridley, and Kraid, all of whom were destroyed by Samus Aran. However, Samus has tracked the space pirates to Tallon IV and must now enter the planet to destroy them once and for all before they have a chance to rebuild their destructive forces...