Worm is a self-published web serial by John C. "Wildbow" McCrae and the first installment of the Parahumans series, known for subverting and playing with common tropes and themes of superhero fiction.

Following his appearance, a fraction of humans gain superpowers if placed in a traumatic and stressful situation, known in-story as a "trigger event".

In 1989, after a parahuman dies trying to prevent a riot, superpowered serial killers, thieves, cults, and gang members begin to increasingly threaten public safety.

To adequately prepare humanity for future attacks and to manage the growing villain population, four prominent heroes form the Protectorate, an organization subordinate to the PRT dedicated to cooperation among superheroes.

Two more monsters (collectively referred to as "Endbringers") appear and begin attacking cities across the planet, causing the loss of millions of lives, as well as catastrophic and irreversible economic and geographic damage.

The story is set in the fictitious city of Brockton Bay, a formerly wealthy port that has severely declined after Endbringer attacks led to the collapse of the shipping industry.

On her first night out in costume, she defeats a superpowered gang leader and is subsequently mistaken for a villain by a team of teenage parahuman thieves known as the Undersiders who work jobs for a mysterious benefactor.

She ultimately finds herself unable to betray the Undersiders and becomes fully committed to them, adopting the moniker "Skitter" and abandoning her dream of becoming a superhero.

In the aftermath, Coil directs the Undersiders and fellow local villains the Travelers in seizing territory and they begin to operate as makeshift warlords in the ruined city.

The Travelers struggle to find a cure for their fifth teammate, Noelle, whose condition is undisclosed and is living in a highly-secure vault in Coil’s base.

When Jack Slash, the theatrical leader of a notorious gang of parahuman serial killers known as the Slaughterhouse Nine, invades Brockton Bay, Dinah predicts he will bring about the end of the world in two years if not stopped.

The city weathers the incursion, but its parahumans fail to kill either Jack or his prized protege Bonesaw, a young girl kidnapped and moulded by the gang of serial killers.

However, as a final act of vengeance, Coil unleashes Noelle (now entitled “Echidna”), who is revealed to be a monstrous parahuman with power and lethality on par with the Endbringers.

Tensions with the authorities later come to a head when Protectorate heroes arrive at a school Taylor is visiting in an attempt to arrest her, publicly revealing her identity as Skitter in ensuing standoff.

Despite the overwhelming advantage that Dinah's abilities had given the heroes, Taylor leverages her reputation and the Protectorate's dwindling popularity to convince almost a hundred students to help her escape, and flees to the safety of her territory.

The Undersiders then continue with their operations in Brockton Bay, later carrying out an attack against the PRT local headquarters in retaliation for outing Skitter and as a show of force to deter rival gangs from action.

In response, Taylor devises a daring plan to conditionally surrender to the PRT and Protectorate, in the hopes of gaining a position to force meaningful change in the declining organizations before Dinah's deadline, as well as sparing the rest of the Undersiders from continued persecution by the authorities.

Not long into Weaver's trial period with the Chicago Wards, Behemoth, another of the three Endbringers, surfaces and begins attacking New Delhi, India.

Weaver is instrumental in many capes surviving the conflict and Behemoth's demise, earning her popular renown and recognition as a genuine superhero, as well as cementing her place in the Wards.

Contessa is shown to be the final agent and architect of the interdimensional conspiracy known as Cauldron, suggested to be responsible for many of the previous events of the story with the aim of combating Scion.

Unbeknownst to all her remaining friends and former allies, Taylor survived and is living in exile alongside her father on Earth Aleph, an alternate dimension that had been sealed off from the rest of the multiverse upon Scion's defeat.

With her short and frenetic life as a cape having ended, Taylor intends to settle into a quiet existence with the anonymity afforded to her on Earth Aleph, and later encounters and befriends an alternate version of her late mother.

[19][21] It received substantial attention following a favorable review by author Gavin Scott Williams roughly six months into publication, who praised the story's themes and originality.

[5] Chris Ellis of Ergohacks.com noted that the story "managed to hit every single trigger warning we have listed", but called it "among the best books and universes I’ve ever read.

"[22] Reviewers have praised the story's realism and use of consequences, contrasting it favorably with the tendency for characters to miraculously return from the dead in superhero comic books and films.

[1][10] There is an IRC chatroom established for readers to comment and discuss the story, which is constantly active, as well as communities of fans on a number of online forums.

[29] The interim story arc, Glow-worm, was released beginning October 21, 2017,[30] and the sequel, Ward, featuring a new protagonist, began serialization on November 11, 2017,[31] and was concluded on May 2, 2020.