It consists of a core five-issue eponymous miniseries written by Jeph Loeb and illustrated by David Finch that was published from January to September 2009, and a number of tie-in books.
The storyline deals with Magneto's attempts to destroy the world following the apparent deaths of his children, Scarlet Witch and Quicksilver in The Ultimates 3.
The series mainly builds on the events of Ultimates 3, in which the villainous robot Ultron shoots and kills the Scarlet Witch.
Before escaping the Ultimates, Magneto is able to steal Thor's hammer which he uses, along with his magnetic abilities, to reverse the Earth's polarity.
As Beast and Nightcrawler are caught in the tsunami, Angel carries an unconscious Dazzler from underwater to the top of a building.
The Invisible Woman uses a massive force field to push all the water back out of the city without affecting civilians or buildings, but this puts her in a coma.
Professor X states that millions have died and telepathically informs many of the world's superheroes that Magneto is responsible for the destruction, having made use of a doomsday attack that Xavier knew he had but never believed he would use.
Meanwhile, Doctor Doom and Zarda confront Reed Richards, and forge a plan to retrieve Nick Fury from the Supreme Power universe.
Meanwhile at Xavier's Institute for Gifted Children, Magneto confronts Professor X and tells him that the deaths of Quicksilver and Scarlet Witch have spurred him to exterminate the entire human race.
He instructs Iron Man to take Wasp's body and find a file titled "The Jocasta Project".
Captain America orders the Ultimates to gather all the remaining heroes and lead them in an assault on Magneto's citadel.
[4] Kitty Pryde leaves to search for Spider-Man, who was caught in an explosion inside the Sanctum Sanctorum, the home of Doctor Strange.
Meanwhile in the Supreme Power universe, Richards, Doom, Zarda, and Arcanna approach the exiled Nick Fury.
Doom explains that he killed her in an attempt to overthrow humanity himself, but never expected Magneto to seek vengeance upon the world.
Nick Fury arrives with Mister Fantastic, Doctor Doom, and Zarda, and implements his contingency plan.
Using Jean's telepathy, Fury transmits his memories to Magneto, showing him that the existence of mutants was in fact the result of a misguided genetic super-soldier experiment (the decades-ago merging of Nick Fury's super-soldier blood and the DNA of Wolverine, thereafter alternately known as "Mutant Zero") and not the "divine calling" that Magneto had long thought it was.
He then takes Magneto's helmet and swears to carry on his father's dream, all while in the presence of an unknown mastermind – a woman whose identity is hidden in the shadows.
[14] Criticism of Loeb's writing was more common in reviews of subsequent issues,[15] and universal by the time of the series' conclusion.
[16] David Finch's art generally drew more praise,[12][15][16] though even that element was not without its critics, with some reviewers taking issue with Finch's focus on characters' physical beauty over expressiveness,[17] and more than one reviewer criticizing him for his depiction of Carol Danvers's breast size.
[18][19] Schedeen gave the series' final issue a scathing review, saying, "Ultimatum is one of the worst comics I have ever read," and called it "the ultimate nightmare.
"[17] Criticism of Loeb's writing centered on his dialogue, the number of characters he killed off, and inconsistent characterization and storytelling.