Source plot synopsis — includes the ending
Five decades prior, the Chozo race fell after a meteor impacted on the planet Tallon IV. The meteor contaminated the planet with a corruptive, mutagenic substance that the villainous Space Pirates later named Phazon, and also brought with it a creature known to the Chozo as "The Worm". A large containment field emitter of the Artifact Temple in the Tallon Overworld area was built as a seal to the meteor's energies and influence within the crater where it landed, which the Space Pirates attempt to disable or bypass in order to gain better access to extract the Phazon. The containment field is controlled by twelve Chozo artifacts that are scattered around the planet.
Not long after defeating Mother Brain and Space Pirate forces on the planet Zebes, Samus Aran intercepts a distress signal from the Space Pirate frigate Orpheon, whose crew have been slaughtered by the Pirates' own genetically modified, experimental subjects. At the ship's core, she battles with the Parasite Queen, a giant version of the tiny parasites aboard the ship. The Parasite Queen is defeated and falls into the ship's reactor core, initiating the destruction of the ship. While Samus is escaping from the frigate, she encounters a cybernetic version of Ridley called Meta Ridley, who also escapes. During her escape, an explosion damages Samus' suit, causing some of her abilities to malfunction. Samus escapes the frigate and chases Ridley in her gunship towards the nearby planet Tallon IV.
After landing in the Tallon Overworld, Samus explores nearby areas of Tallon IV and discovers ruins of an ancient Chozo settlement. As she explores the ruins, she learns that the Chozo on the planet had been killed off by the Phazon infesting the planet, which originated from a meteor that impacted on the planet many years ago. After regaining her lost abilities in the ruins, as well as defeating a mutated plant creature that was poisoning the local water supply, Samus finds her way to the Magmoor Caverns, a series of magma-filled tunnels, which are used by the Space Pirates as a source of geothermal power. Following the tunnels, Samus travels to the Phendrana Drifts, a cold, mountainous region which is home to another ancient Chozo ruin and a Space Pirate research laboratory, Glacial One, used to study the Metroids. After obtaining new abilities, Samus explores the wreckage of the crashed Orpheon and then infiltrates the Phazon Mines, where she learns the outcome of the Phazon experimentation project, including the Metroid Prime, a creature that had come to Tallon IV with the meteor. Advancing deeper into the mines, Samus fights her way through the Phazon-enhanced Space Pirates and obtains the Phazon Suit after defeating the monstrous Omega Pirate.
At some point, Samus discovers the Artifact Temple that the Chozo built to contain the Metroid Prime and to stop the Phazon from spreading over the planet. To gain access to the meteor's Impact Crater, Samus must collect and unite the twelve Chozo artifacts. As Samus returns to the temple with the artifacts, Meta Ridley appears and attacks her. Samus defeats Ridley and enters the Impact Crater, where she finds the Metroid Prime. After she defeats it, the Metroid Prime absorbs Samus' Phazon Suit and explodes. Samus escapes the collapsing crater and leaves Tallon IV in her ship. If the player completes the game with all of the items obtained, a post-credits scene shows Metroid Prime reconstructing itself into a body resembling Samus.
Not long after defeating Mother Brain and Space Pirate forces on the planet Zebes, Samus Aran intercepts a distress signal from the Space Pirate frigate Orpheon, whose crew have been slaughtered by the Pirates' own genetically modified, experimental subjects. At the ship's core, she battles with the Parasite Queen, a giant version of the tiny parasites aboard the ship. The Parasite Queen is defeated and falls into the ship's reactor core, initiating the destruction of the ship. While Samus is escaping from the frigate, she encounters a cybernetic version of Ridley called Meta Ridley, who also escapes. During her escape, an explosion damages Samus' suit, causing some of her abilities to malfunction. Samus escapes the frigate and chases Ridley in her gunship towards the nearby planet Tallon IV.
After landing in the Tallon Overworld, Samus explores nearby areas of Tallon IV and discovers ruins of an ancient Chozo settlement. As she explores the ruins, she learns that the Chozo on the planet had been killed off by the Phazon infesting the planet, which originated from a meteor that impacted on the planet many years ago. After regaining her lost abilities in the ruins, as well as defeating a mutated plant creature that was poisoning the local water supply, Samus finds her way to the Magmoor Caverns, a series of magma-filled tunnels, which are used by the Space Pirates as a source of geothermal power. Following the tunnels, Samus travels to the Phendrana Drifts, a cold, mountainous region which is home to another ancient Chozo ruin and a Space Pirate research laboratory, Glacial One, used to study the Metroids. After obtaining new abilities, Samus explores the wreckage of the crashed Orpheon and then infiltrates the Phazon Mines, where she learns the outcome of the Phazon experimentation project, including the Metroid Prime, a creature that had come to Tallon IV with the meteor. Advancing deeper into the mines, Samus fights her way through the Phazon-enhanced Space Pirates and obtains the Phazon Suit after defeating the monstrous Omega Pirate.
At some point, Samus discovers the Artifact Temple that the Chozo built to contain the Metroid Prime and to stop the Phazon from spreading over the planet. To gain access to the meteor's Impact Crater, Samus must collect and unite the twelve Chozo artifacts. As Samus returns to the temple with the artifacts, Meta Ridley appears and attacks her. Samus defeats Ridley and enters the Impact Crater, where she finds the Metroid Prime. After she defeats it, the Metroid Prime absorbs Samus' Phazon Suit and explodes. Samus escapes the collapsing crater and leaves Tallon IV in her ship. If the player completes the game with all of the items obtained, a post-credits scene shows Metroid Prime reconstructing itself into a body resembling Samus.
Sources and content license
Source and revision history ↗ · Adapted from Wikipedia contributors, Metroid Prime. Section headings and formatting adjusted. · Content license