How complex can Metroid really be? It’s basically an extended riff on Ridley Scott’s Alien. An outer space bounty hunter puts on an Iron Man suit, travels to exotic planets, and hunts extraterrestrial parasites. That’s all there is to it, right? Metroid isn’t the type of game you play for the plot. It’s about exploring strange worlds, collecting power-ups, and unlocking new ways to proceed. If there’s any story, that’s a bonus, not a feature.
But Metroid is complicated. It’s so, so complicated. It has clones. It has evil doppelgangers — yes, more than one. Its recurring big bad is an artificial brain in a jar. It stars numerous all-knowing alien races, contains at least two outer-space infections, features a couple of genocides, and is downright lousy with bio-engineered super-weapons. It is a lot.
And poor Samus Aran, Metroid‘s reliable hero, is stuck in the middle of it all. We’re not sure how she can keep track of it all. If you’re here, the chances are that you can’t, either. Metroid lore is just as twisty and complicated as any of Zebes’ underground mazes, so follow our guide closely. When things get this wild, it’s easy to get lost.
Before the beginning
The Metroid manga may not be a video game, but it’s widely accepted as Metroid canon. Launched in 2004 in order to tie in with the release of Metroid: Zero Mission, Koji Tazawa and Kenji Ishikawa’s two-volume comic reveals Samus’ backstory. It’s a crucial piece of Metroid lore for one big reason: it ties everything else together.
In the beginning, three-year-old Samus Aran lived with her father and mother in a mining colony on a distant planet. When the Space Pirates attacked, everything changed. Despite Samus’ father’s best efforts, the Pirates, led by a dragon-like creature named Ridley, killed everyone in the colony save Samus, who was rescued by a bird-like race called the Chozo and taken to their home planet, Zebes. There, the Chozo infused Samus with their own DNA and raised her to be a fearsome warrior.
The Chozo weren’t all good, however. Away from the Federation’s prying eyes, the Chozo bioengineered a race of energy-sucking parasites called Metroids, who were designed to stop the shape-shifting X Parasites. Their colony on Zebes was also run by a biological computer — i.e., a giant brain in a tube — named Mother Brain, who was tasked with preserving Chozo history at any cost. Any cost.
Yeah, that doesn’t end well.
The Metroid games don’t go in order, but the first game actually is the first game — sort of. While Metroid, which debuted on the NES in 1987, kicks off both the franchise and the ongoing saga, it’s light on plot details. A full recount of Samus Aran’s first Metroid-based adventure didn’t arrive until 2004, when a Metroid remake called Metroid: Zero Mission hit the Game Boy Advance and the Metroid manga arrived to fill in the gaps.
While Samus is off serving in the Federation Police, the Ridley Space Pirates attack Zebes. Disobeying her commanding officer, Adam Malkovich, Samus abandons her post and rushes to her adopted homeworld. There, she discovers that things have gone sideways: Mother Brain has deemed the Chozo obsolete and taken control of both the Pirates and the planet. Samus and her friends try to stop the invasion, but when Ridley attacks Samus suffers a PTSD attack. The mission fails, and Zebes is lost.
A few years later, Samus has retired from military service and is working as a bounty hunter when the Galactic Federation gives her a mission: a Federation research vessel transporting Metroids from SR388 was attacked by the Space Pirates, who stole its cargo and took the creatures back to Zebes, with plans to breed the Metroids as weapons. Samus is the only woman who can stop them. She does. Samus storms Zebes, defeats Ridley (and his robotic doppelganger), kills Mother Brain, and destroys the Metroids. And that’s the end of the story, right?
Oh, if only.
She’s just going through a Phazon
Okay, so, it turns out that Samus didn’t destroy all of the Space Pirates on Zebes. One ship, Frigate Orpheon, escaped Samus’ attack and fled to Tallon IV, where its passengers decided to conduct another round of unsavory experiments. Using a radioactive substance called Phazon, the Space Pirates on Frigate Orpheon transformed Tallon IV’s native wildlife and some spare Metroids into biological weapons. Unfortunately, some of those augmented creatures escaped, decimating the Orpheon and killing its crew.
Samus picks up the Orpheon‘s distress signal and investigates, and that’s where Metroid Prime begins. Frigate Orpheon itself ends up being a dead end — although Ridley, artificially resurrected and cybernetically enhanced, pops up to give Samus a hard time — but Samus has better luck on Tallon IV. As Samus explores the planet, she learns that the Phazon arrived on Tallon IV via meteor, which the Chozo locked away in a temple. She also learns that the Space Pirates have been injecting themselves and Metroids with Phazon, which isn’t great, but she does get a cool Phazon-enhanced suit out of it, so, y’know. Silver linings and all.
Eventually, Samus unlocks the temple and faces off against the "Metroid Prime," which serves as the source of all of Tallon IV’s Phazon. She beats it in battle and clears Tallon IV of Phazon, but that’s just the beginning: after Samus leaves, the Metroid Prime fuses with Samus’ discarded Phazon Suit and re-emerges as Dark Samus. Uh oh.
Two is company, seven is a crowd
Samus’ battle against Phazon and Dark Samus gets put on hold in the DS exclusive Metroid Prime: Hunters, in which Samus travels to the Alimbic Cluster to investigate a telepathic message at the Federation’s request. The message, which is delivered in thousands of different languages, warns that "the secret to ultimate power lies in the Alimbic Cluster." Samus’ mission is to either retrieve the presumed superweapon or to destroy it before it can fall into enemy hands.
Problem is, Samus doesn’t travel to the Alimbic Cluster alone. The message is also intercepted by six of the galaxy’s most fearsome bounty hunters, each of whom want the ultimate power for themselves. Oh, and just to complicate things further, Samus eventually learns that the Alimbic people were a peace-loving race who were driven to extinction when they were attacked by a creature called Gorea. The last surviving Alimbics sacrificed themselves in order to lock Gorea away, but Gorea had a back-up plan: it turns out that the psychic message was sent by Gorea itself in an attempt to secure its freedom.
It’s all a big mess. While fending off her peers, Samus tracks down eight artifacts and unwittingly opens Gorea’s prison, the Infinity Void, forcing the bounty hunters to put aside their differences to take Gorea down. They do, with some help from an old Alimbic weapon, and head home empty-handed.
Now, back to the main plot: Tallon IV wasn’t the only planet struck by a Phazon meteor. Aether, home to the Luminoth, was too. When Phazon arrived on Aether, however, it didn’t just hurt the environment. It split the planet into two, with the new half, Dark Aether, inhabiting an entirely different dimension.The Luminoth and Dark Aether’s inhabitants, the Ing, go to the war, with the fate of both planets at stake.
Naturally, Samus gets caught up in the middle. The Space Pirates, who never met a superweapon they didn’t like, settle on Aether in order to harvest Phazon. Galactic Marines discover the Pirate operation and try to stop it. When they fail, the Federation sends Samus in to clean up their mess. Before long, Samus is on a mission to rescue the near-extinct Luminoth and return Aether to light, hopping between dimensions and fighting off the combined forces of the Space Pirates, the Ing, and Dark Samus along the way.
Samus succeeds, of course — she wouldn’t be much of a hero if she didn’t — but not before Dark Samus forces her into one final showdown. Samus beats Dark Samus and leaves, but a post-credits scene reveals that Dark Samus is able to reform herself. As Metroid Prime 2: Echoes fades to black, Dark Samus is humiliated, angry, and bent on revenge.
Dark Samus’ last stand
If Metroid Prime and Metroid Prime 2 were mere skirmishes, Metroid Prime 3: Corruption is all-out war. The Space Pirates have reformed under Dark Samus’ leadership. Phazon meteors called Leviathan Seeds are striking planets all over the galaxy. The Federation’s Mother Brain-like organic computers, the Aurora Units, are falling prey to a Phazon-based virus. All of this comes to a head on the planet Norion, where Samus and her fellow bounty hunters repel a Space Pirate attack and stop a Leviathan Seed from destroying a Federation base.
There’s a cost, however: Samus and the other bounty hunters are contaminated by Phazon during the mission, and while they get cool new powers as a result, the substance is slowly killing them. The corrupted bounty hunters go missing while investigating Leviathan Seeds on distant worlds. Samus is the only one left who can beat her comrades, stop the Seeds from contaminating multiple worlds, free the Aurora Units, and conquer Dark Samus’ forces. Oh, yeah, Ridley’s back too, having regenerated some of his body parts thanks to some Phazon influence.
Samus’ Phazon corruption gets worse, but with some help from the Federation she eventually makes her way to Phaaze, the source of all Phazon. Samus and Dark Samus race to the planet’s core, where Samus puts her doppelganger down and destroys the planet, ridding the galaxy of Phazon once and for all. After paying her respects to her fallen peers, Samus heads back into space — but unknown to her, she’s followed by Sylux, one of the bounty hunters introduced in Metroid Prime: Hunters. He’s not a nice guy.
Tying up loose ends, the Federation Force way
Following Dark Samus’ demise, the Space Pirates are floundering, and the Federation thinks it’s the perfect time to take them out. And so, the government dispatches a group of mech-wearing soldiers to the Bermuda System, where Samus discovered that the Space Pirates are building a battleship called the Doomseye before she disappeared.
In the 3DS game Metroid Prime: Federation Force, it’s up to you and your friends to destroy the Doomseye, reverse the Pirate’s newfound size-changing abilities, and rescue Samus. Yes, that’s right: Federation Force is the only game in the series in which Samus isn’t the main character, although she still plays a critical role. The Federation Force and their mechs destroy the cloaking device that keeps the Doomseye hidden, but can’t stop the ship from decimating the Galactic Federation’s fleet. They still manage to infiltrate the Doomseye, rescue a giant and mind-controlled Samus, and blow up the battleship, so it’s all good.
Well, mostly good. Samus rescues the Federation Force from the cold depths of space, and everyone heads on their separate ways, but nobody seems to notice that Sylux has infiltrated a Federation research facility and stolen a Metroid egg. That plot point hasn’t paid off yet — although with Metroid Prime 4 on the distant horizon, it’s probably just a matter of time.
With the pirates out of the way, at least for now, Samus can focus on the galaxy’s other big problem: the Metroids. In Metroid 2 and its remake, Metroid: Samus Returns, that’s exactly what she does. Samus travels to SR388, the Metroid homeworld, to end their threat for good only to discover that the Chozo colony that bred the gelatinous parasites has been overrun, and that the Metroids have been mutating into other, more monstrous forms.
Still, after everything Samus has been through, some casual genocide is a piece of cake. It doesn’t take long for the bounty hunter to dive deep into the planet, find the Metroids, and wipe them out. All of them. Well, okay, almost all of them. Just when it looks like Samus is finished and the Metroids are gone, a baby Metroid hatches from an egg and mistakes Samus for its mother, imprinting on the bounty hunter immediately. Samus is touched and refuses to kill the creature.
That’s when Ridley, mostly healed thanks to his former encounters with Phazon, attacks. Samus fends him off but doesn’t kill him, and escapes with the baby Metroid in her possession. It’s not clear what happens to Ridley next, but he either escapes on his own or is rescued by the Space Pirates. Oh, and by the way: as Samus Returns‘ post-credit sequence reveals, SR388’s shape-shifting X Parasites — the very beings that the Metroids were created to eliminate in the first place — have returned. That’ll be important later.
Back to where it all began
Samus didn’t kill the baby Metroid, but her maternal instincts have a limit, and life-sucking blobs seem to be it. Instead of raising the Metroid as her own, Samus donates the infant to a Galactic Federation space station for research. That seems like a good idea until Ridley attacks the station and steals the Metroid, taking it back to Zebes.
By this point, you probably know what’s coming. In Super Metroid, Samus travels back to Zebes again to stop the Ridley and the Pirates, only to discover that they’ve rebuilt their entire base. Those Metroid cloning facilities? They’re back, along with some newly-built Metroid larvae and old, discarded Mochtroids, i.e., the Space Pirates’ first, flawed attempts at bioengineering Metroid offspring. Mother Brain resurfaces, too, and while it’s not clear how, there are two possibilities: the Space Pirates could’ve rebuilt her — remember, she’s a computer, not a real girl — or, as Metroid Prime 3 implies, the new Mother Brain might be an advanced Aurora Unit. Either way, she’s back, and she’s up to no good.
It takes Samus a while to find the baby Metroid. In the interim, the infant grows to a gigantic size, and doesn’t recognize Samus when they reunite. The baby attacks but realizes its mistake before Samus dies, and later sacrifices itself to help Samus defeat Mother Brain. D’aw. Unfortunately, killing Mother Brain dooms the entire planet, and Samus barely escapes before Zebes explodes, taking Ridley, the Metroids, the Space Pirates, and the last remnants of the Chozo with it.
Attack of the clones
So far, Metroid has followed a standard formula. The Space Pirates are the bad guys. The people of the Galactic Federation are the good guys. Metroid: Other M complicates that. In Other M, a small group of Federation soldiers and scientists are creating new, more powerful Metroids from the remnants of baby Metroid DNA found on Samus’ suit. They’re cloning Space Pirates, hoping to build a special ops force. They accidentally resurrected Ridley. They made an AI based on Mother freakin’ Brain, which they called MB and tried to use to control their experimental Metroid offspring.
MB eventually gained sentience and turned on her creators, then freed all of these genetic experiments, using her psychic powers to lead them on a massacre. Samus discovers all of this about six months after Zebes exploded. While still grieving for the baby Metroid, Samus answers Bergman’s distress call, which leads her to the ship where all of this research was taking place.
This time, however, Samus isn’t alone. She’s joined by the Galactic Federation 07th Platoon, which her old commander, Adam Malkovich, oversees. The familiar faces just make things worse. An encounter with the juvenile Ridley clone triggers Samus’ long-dormant PTSD. A traitor in the 07th Platoon and the whole illegal experiment thing makes Samus doubt the Federation’s intentions. Malkovich sacrifices himself to stop the Metroid clones, robbing Samus of yet another father figure. It’s a huge bummer. Samus saves the day — she always does — but all of this conflict is starting to take its toll.
It doesn’t get better. In Metroid Fusion, the Federation sends a research team to SR388, and they ask Samus to provide security. However, with the Metroid predators out of the picture, the X Parasite has flourished, and one attacks Samus almost immediately. Both Samus and her suit are contaminated. The parasite in Samus’ suit uses its powers to transform into SA-X, a Dark Samus-like doppelganger. Samus herself is rushed to a Federation medical facility, where she’s saved by a vaccine synthesized from the remaining baby Metroid cells. As she puts it, "The hatchling had saved me once again."
As a result of the vaccine, Samus can absorb X Parasites. That’s good. Like Metroids, she’s also vulnerable to cold. Less good. Also, SA-X and its fellow X Parasites are now wreaking havoc on the station where Samus is staying. Not good at all. With the help of her ship’s chatty new computer, named Adam after Samus’ former boss, Samus begins hunting down X Parasites, only to learn that the Federation has been cloning Metroids — again — in secret. That’s bad.
To compound the problem, SA-X has been asexually reproducing, meaning there are multiple copies out there, and the Galactic Federation wants to capture SA-X and use it as a weapon. By this point, Samus has had enough. With Adam’s help (and a surprise assist from SA-X), Samus sets the station on a collision course with SR388, destroying the X Parasites, the SA-X duplicates, the Metroid clones, and any other baddies hiding out there.