This article is about the in-universe mission. For the game, see Metroid: Zero Mission.
Planet Zebes...I called this place home once, in peaceful times, long before evil haunted the caverns below. Now, I shall finally tell the tale of my first battle here.... My so-called Zero Mission.

Samus Aran in the opening of Metroid: Zero Mission

Samus Aran's Zero Mission is her first and most famous venture. During it, she defeated the Zebesian Space Pirates and their leader, Mother Brain on planet Zebes. The Zero Mission is chronicled in the very first Metroid and its remake, Metroid: Zero Mission.


Chozo's Zebes[]

Samus growing up on Zebes

The planet Zebes was home to one of the many Chozo civilizations on planets across the universe. When the Chozo realized they were dying out, they became key advisers to the still-young Galactic Federation, hoping that the Federation would achieve the Chozo's dream of bringing true peace to the universe. They built the AI Mother Brain, with the goals of bringing order to the universe, and to help fight the X Parasite via the creation of Metroids.

When the neighboring planet K-2L was attacked by pirates, the Chozo of Zebes found one girl amongst the ruins. The girl, aged 3–5, was a young Samus Aran. She was brought to Zebes, infused with Chozo DNA, given the Power Suit and trained until she was ready to join the Federation Police.

Space Pirates Invasion[]

Space Pirates attacking Zebes

After Samus left, Mother Brain betrayed the Chozo and called in the Space Pirates. She calculated that the best way to bring order to the universe was to pit the Space Pirates and Federation against each other and "reset the universe to zero".[1] The Space Pirates invaded Jigrad to distract the Federation,[2] and used the Space Pirate Flagship to disable Zebes' Planetary Protection Shield with a micro black hole.[3] The peaceful Chozo either surrendered or fled with the first Metroid specimen. This was the first time the Space Pirates had ever encountered a Metroid.[4]

Samus' Infiltration of Zebes[]

Samus was given a 48-hour window to infiltrate Zebes before the Federation Fleet arrived.[3] She traveled to Zebes with Kreatz and Commander Mauk and discovered the Space Pirates' presence and Mother Brain's betrayal. Having the element of surprise on their side, Samus and her team managed to rescue most of the Chozo prisoners. However, one Chozo, Gray Voice, gave his life trying to destroy Mother Brain. This allowed Samus, Kreatz, Mauk and the Chozo prisoners enough time to escape Zebes.[5]

Federation vs. Space Pirates[]

The research vessel Marina under attack, lead to the space pirates acquiring the Metroid.

The Federation fleets eventually arrived, and promptly performed an orbital bombardment of Zebes. However, hidden deep in Tourian, this did not stop the Pirates, or their leader. For many years[6] the Space Pirates, under the leadership of Mother Brain, fought the Federation with renewed fervor. Meanwhile, Mother Brain used the ecosystem of Zebes to turn the planet into her own personal fortress.[7] In the year 20X5 of the Cosmic Calendar, the Space Pirates attacked the Space Research Vessel Marina and seized capsules containing samples of an species unknown to the Federation, that had been discovered on planet SR388. The Space Pirates' objective was to acquire these floating organisms, which were incredibly dangerous as they could latch onto any other organism and drain its energy. Furthermore, it was possible to replicate them in vast numbers in just 24 hours by exposing them to beta radiation. The hypothesis that the creatures were responsible for one of the greatest mysteries in the entire galaxy — the extinction of all life on planet SR388 — was generally accepted as fact. Its name was Metroid. The Space Pirates were breeding Metroids and using them as biological weapons,[6] which tipped the balance of power in their favor, but danger arose as the Pirates were unknowingly losing control of the Metroids.

Metroids being used as bioweapons

It was at this time that the Federation attempted to launch a full-scale assault on the planet Zebes, but the Pirate resistance was strong, forcing the Federation to retreat. Meanwhile, deep within the center of the Pirate fortress, the preparations for multiplying more Metroids were steadily progressing.

As a last resort, the Police decided to send a lone Bounty Hunter to penetrate the Pirate base, eradicate all Metroids and destroy Mother Brain. The hunter chosen for such a great task was Samus Aran, considered by many to be the greatest of all bounty hunters. Samus had successfully completed numerous missions that others had thought impossible, making her an excellent candidate.[8]

Co-current Events[]

VIXIV in battle at the time of Samus's Zero Mission

Ridley's flagship, known as the Space Pirate Mother Ship, carried out hit and run Metroid attacks on Federation bases. The ship was detected by Commander Mauk and the co-ordinates were sent back to Galactic Federation Headquarters.[7] A large battle between Federation forces (including Adam Malkovich commanding the Federation Army Special Ops Battleship VIXIV) and Space Pirates commenced. When Samus's presence on Zebes was detected, Ridley's flagship escaped the battle to reinforce Zebes.[9] It is known that during Samus's Zero Mission, the Space Pirates were also attacking Mauk's home planet, Jamoru. Mauk and Kreatz made a two-man stand against the Space Pirates here.[9]


Samus eventually landed on the surface of Zebes and began exploring the planet; she quickly discovered the extent to which Mother Brain had altered the ecosystems to serve her evil will.[10] The Bounty Hunter destroyed Ridley's comrade Kraid, attracting the attention of Ridley himself to Zebes. When his flagship landed on Zebes, Samus engaged in a fierce duel with her arch-nemesis until he, too, was defeated.

After traversing all of the various caverns and regions of the planet, Samus finally found and destroyed Mother Brain and the Metroids, the latter of which massacred the Zebesian forces in Tourian. However, upon leaving the planet after her successful mission, Space Pirate vessels attacked her Starship. Samus crash-landed back on Zebes near the Space Pirate Mother Ship; she survived, but her Starship and even her Power Suit were destroyed in the explosion, leaving her virtually defenseless in only a blue form-fitting suit and a taser dubbed the "Paralyzer".

Samus's Zero Mission is complete

While searching the Mother Ship for a way to escape, Samus discovered the nearby ruins of an ancient Chozo temple known as Chozodia. There, she passed the Ruins Test and gained the Legendary Power Suit, which forevermore became her signiture attire. With her armor restored and further enhanced than ever before, Samus stormed the Mother Ship, leaving behind many dead Pirates. She encountered the Ridley Robot, a mechanized form of Ridley that had taken command of the ship during Ridley's absence. Upon destroying it, Samus was able to successfully escape the planet (and the self-destructing Mother Ship) by using one of the Escape Ships.


A survivor of the fall of Zebes, the Research Frigate Orpheon

Due to the destruction of Tourian and the Mother Ship, it was thought that all the Space Pirates' research on Metroids was destroyed. However, three research frigates: Orpheon, Siriacus and Vol Paragom were in orbit of Zebes at the time of its fall and managed to retreat. The Orpheon went to nearby planet Tallon IV and docked at the Vortex Outpost, where cybernetic augmentation of Ridley was completed. The Orpheon also performed further Metroid research, including the Metroids' reaction to Phazon.[11]

Meanwhile, back on Zebes, the Federation was quick to occupy the planet, following the elimination of the Pirates inhabiting the planet. Roughly 200 researchers came to study Zebes for its Urthic ore and Chozo ruins.[12]

During the time following Samus' Zero Mission, the Space Pirates stopped being such a prevalent opposing force. Samus was surprised to see the Space Pirates again three years later,[13] when investigating a distress beacon from the Orpheon. However, the following years would see a rise in Pirate activity due to a desire for more Phazon and new leadership.

Eventually the Space Pirates would build up their forces on Zebes again, including remaking Mother Brain and Kraid.[14] Samus would destroy Mother Brain, Kraid, Ridley, Tourian and the entire Space Pirate operation a second time, during the Raid on Planet Zebes.


  1. ^ Metroid Manga: Chapter 12:Pheonix III
  2. ^ Metroid Manga: Chapter 3:First Battle
  3. ^ a b Metroid Manga: Chapter 5:Crisis
  4. ^ Metroid Manga: Chapter 6:Infiltration
  5. ^ Metroid Manga: Chapter 6 - 12, Samus's Infiltration of Zebes
  6. ^ a b Metroid Manga: Chapter 13:Hunter
  7. ^ a b Metroid Manga: Chapter 14:Confidence
  8. ^ Metroid / Metroid: Zero Mission manuals
  9. ^ a b Metroid Manga: Chapter 16:The Successors
  10. ^ Metroid Manga: Chapter 15:Tooth and Nail
  11. ^ Metroid Prime Space Pirate Log: Fall of Zebes
  12. ^ Metroid Prime website
  13. ^ Metroid Prime comic
  14. ^ Super Metroid