Genosha, introduced in previous issues of Uncanny X-Men, is an island nation that's prospered through the enslavement, brainwashing and genetic modification of mutants, reducing them to nameless, subservient "mutates" with no lives of their own. For the most part, this is limited to exploiting Genosha's own citizens - but their press gang has clashed with the X-Men in the past, and Genosha's government now has a score to settle.
When a Genoshan military team operating illegally in the USA targets Xavier's School for Gifted Youngsters, they manage to capture some of the younger students - teleporting them back to Genosha for "processing". The raid aggravates existing tensions between Genosha and the USA - and, unsurprisingly, leads to a combined team of X-Men, New Mutants and X-Factor members heading to Genosha to fight an entire nation and rescue their friends.
There are some things that the mutants aren't aware of, though. One is that an old enemy - the mutant-hating immortal Cameron Hodge - is now in Genosha, allied with the government and newly equipped with a powerful robotic body. The other is that Havok, a missing X-Man and brother to X-Factor's leader Cyclops, is also in Genosha - but, amnesiac and brainwashed, he's now fighting alongside their mutant-hunting Magistrates.
The nine-part saga cycles through Uncanny X-Men, New Mutants, and X-Factor.
X-Tinction Agenda provides examples of:
- Amnesiac Hero: At the start of the arc, Havok has lost his memory and is now working for Genosha, oppressing other mutants as one of their Magistrates.
- Big Bad: Cameron Hodge, the anti-mutant extremist from previous X-Factor stories. Angel decapitated him, but his Deal with the Devil granted him Immortality and he's now returned as a severed head in a scorpion-styled cyborg body.
- Bittersweet Ending: Hodge is defeated and the president of Genosha is deposed. Wipeout and the Genegineer are both dead, limiting Genosha's ability to capture and convert mutants. But Genosha, as an apartheid nation built on mutant slavery, still stands - and its existing Mutates are still brainwashed, nameless slaves. The heroes have paid a high price - although Havok's regained his memories, Warlock is dead and Wolfsbane's been partially converted into a mutate.
- Brought Down to Badass: Wipeout's power cancels other mutants' abilities, and it's almost immediately used on everyone the Genoshans capture. Many characters spend most of the crossover without their powers.
- Call-Back:
- Seeing the X groups chained to the walls, Beast recalls the time Magneto put most of the X-Men in a similar situation (Uncanny X-Men 112-113). He laments that Storm cannot free them like last time. Fortunately she’s no longer the only lock-picking thief of the group…
- Came Back Wrong: The storyline reveals that Cameron Hodge’s Deal with the Devil pact with the demon Nastirh allowed him to survive getting beheaded by Archangel back in X-Factor #34. Unfortunately the pact didn’t grant him full invulnerability or regeneration, so he now exists as a head without a body.
- Combat Tentacles: Hodge's robot form has mechanical tentacles and they're among his preferred melee weapons.
- Death Is Cheap: Rahne calls out Ororo over how unfair it is that X-Men like she and Jean Grey can come back from the dead, but her late teammate Doug Ramsey cannot.
- Dramatis Personae: The Uncanny X-Men issues and X-Factor #61 list the names of the characters of the chapter.
- Enemy Civil War: Hodge and the Genegineer have very different aims and are actively trying to destroy each other towards the end of the crossover. Hodge kills him, but by that point the Genegineer's already put plans in place to help the mutants defeat Hodge.
- Everyone Calls Him "Barkeep": The Genoshan President is only referred to by her title, never by name.
- Fantastic Racism: Genosha is a whole nation built on this. Mutants - including those who only have potential powers - are identified, genetically modified (e.g. to activate dormant powers), brainwashed and sealed into suits, then used as a slave underclass.
- Fountain of Youth: It's inherited from the previous stories rather than introduced within X-Tinction Agenda itself, but one plot point is that Storm's been regressed to her early teenage years. She still has her adult mind, powers and skills - but no longer has the physical stamina to fully fuel those powers. The Genegineer's tampering helpfully resets her to her proper age by the end of the crossover.
- Frame-Up: Cameron Hodge kills Wipeout and frames Havok for his death.
- Improvised Lock Pick: Hodge wounds Gambit by a projecting a spike into his thigh, letting it remain there for his discomfort. His hands chained to the wall, Gambit lifts his legs and pulls out the spike with his mouth. Using his feet to hold the projectile, Gambit performs this trope, freeing himself and his fellow captives.
- Intangibility: Hodge's robotic body can phase through solid objects.
- Memory Wipe Exploitation: Discovering an amnesiac Havok is now a Genoshan Magistrate, Hodge has him attack the X-teams at several occasions.
- Military Coup: The Magistrates lead one at the end of the arc, after the Genegineer is killed and the depths of Hodge's insanity become clear. The President, as the sole remaining member of the original trio, is deposed and takes the fall for the attack on the USA.
- The Nudifier: Pipeline teleporting any non-Magistrate person to Genosha causes this trope. Storm, Wolfsbane, Rictor, and Boom Boom arrive in their birthday suits.
- Power Nullifier: Wipeout's ability. He can remove (and restore) the powers of any mutant or mutate.
- Putting the Band Back Together: After nineteen issues of the team being disassembled and the series focusing on individual groups (Storm; Wolverine, Psylocke, & Jubilee; Forge & Banshee), this storyline brings the X-Men back together.
- Sealed Evil in a Can: Hodge's fate. The heroes can't kill him, even when they destroy his cyborg body. So Rictor uses his seismic powers and buries his severed head under the ruins of his Genoshan base.
- Weaponised Teleportation: Pipeline's power lets him teleport enemies back to Genosha. It only teleports people, though, not objects - so they arrive naked, ready to be detained by armed Magistrates (and with his teammate, the Power Nullifier Wipeout, close to hand).
- Against Warlock it's a more direct weapon, although not intentionally - his techno-organic biology means that he's near-fatally drained of energy when he reappears.
- Worf Had the Flu: Wolverine had been dramatically weakened at the time of this storyline; due to getting tortured by the Reavers in Uncanny X-Men 251, his healing factor has been overtaxed keeping him functioning, rendering him a more vulnerable and less capable fighter.
- Xtreme Kool Letterz: The title uses X-Tinction rather than Extinction.
- "Wanted!" Poster: The original advertisement of the crossover was this trope, portraying Wolverine, Archangel, and Cable (each representing Uncanny X-Men, X-Factor, and New Mutants.
- You Are Number 6: As part of the dehumanising conversion process, Genoshan mutates get ID numbers, not names.
- You Are Too Late: When attacked by Genoshan Magistrates on the surface, Storm gets Stevie Hunter down an exterior hatch leading to the X-Men’s headquarters, which then gets closed and locked to keep the Genoshans from finding it. Unfortunately, this also prevents Forge, Banshee, Cable, and Cannonball from immediately aiding Storm and the New Mutants. By the time they reach the surface via a different way, the Genoshans have already captured their teammates and escaped.
