The narrative picks up with the protagonist, Ane, a young woman with the unique ability of parallel thought, finishing a VR game session. She defeats her virtual opponent, securing a bet against her younger sister, Touka, who laments the loss of her ice cream. Ane, who possesses an exceptional talent for multitasking, reveals her intention to transition to a new VRMMORPG, "Mongrel Stacker" (Monsta), developed by Magicraft Company. This is a significant shift, as Ane had previously been banned from VR games due to her parallel thought ability causing bugs, leading her to favor controller-based games. However, Magicraft has reportedly implemented support for parallel thought in Monsta, reigniting her interest.
Ane and Touka discuss the upcoming game, with Touka initially skeptical of Ane's ability to get the game due to her "desire sensor" being broken. However, Ane's confidence stems from her successful application for the game's lottery. On the eve of Monsta's launch, Ane receives two copies of the game, one from winning the lottery and another unexpectedly from Magicraft Company as a thank-you for her feedback, signed by the development representative, Masaru Ingaho. This generosity, while appreciated, makes Ane uneasy, suspecting a hidden motive. She then invites Touka to play, who initially hesitates due to club activities but eventually agrees.
The game begins on August 1st, with Ane and Touka starting character creation. Monsta's main draw is its implementation of non-human avatars, overcoming the phantom limb sensations that plagued previous VR games. However, all avatars are initially humanoid, with the ability to transform into true forms for certain species. The game is set in a post-apocalyptic world called "Serag Ragnarok" after a cataclysm destroyed civilization. The game's developers, Magicraft, have gone above and beyond by sending Ane a list of recommended races based on her parallel thought ability.
Ane chooses the Shoggoth, a shapeless entity that can mimic humans. Her character, Corona, is assigned the "Maid" class and is immediately faced with severe limitations: no experience or magic acquisition, and a vulnerability to magic and [redacted] damage. Her initial spawn point is a disgustingly smelly garbage dump, a brutal start that tests her resolve. She struggles to control her Shoggoth form, eventually learning to manipulate individual cells for movement. After falling through the garbage dump, she finds herself in a cavern filled with other Shoggoths. She eventually masters human transformation and gains some control over her Shoggoth form.
Driven by hunger and the Shoggoth trait of consuming kin to grow, Ane reluctantly consumes a smaller Shoggoth, experiencing temporary madness. This act grants her new skills and titles, including "Bloodline Eater." She then encounters a formidable entity, "The Million of the Blessed," which speaks in an alien tongue and ultimately consumes her, resulting in her death and a new title, "Candidate for the Inheritance of a Million Blessed." She is then forcibly logged out.
Back in the real world, Ane is disoriented and unwell after her traumatic in-game experience. Meanwhile, Monsta enters an unscheduled, extended emergency maintenance period to fix issues related to "madness" status effects, "indeterminate madness," and the garbage dump spawn point, all of which Ane uniquely experienced.
While Monsta is down, Ane decides to revisit a previous game, "Gradual Duel," a fighting game. She logs in and is surprised to find two of the top-ranked players, Pepe and Ronchino, online. She challenges them to a tag-team match, and despite a month's break, her exceptional coordination with her virtual partner (implied to be herself controlling two characters) proves overwhelming, even for the professional gamers. This "Anemone" pair's seamless teamwork is described as monstrous.
After the match, Ane prepares lunch for Touka, who is now free from club activities and eager to play Monsta. Ane explains her forced logout and the subsequent game-wide issues, which Touka finds concerning. As maintenance concludes, they prepare to log back into Monsta.
The narrative then provides character profiles, highlighting Ane's "split personality" and exceptional parallel thought abilities, contrasting with Touka's athletic prowess and unwavering affection for her sister. It also introduces Pepe and Ronchino as professional gamers who are both impressed and intimidated by the Anemone pair.
Upon logging back into Monsta, Ane is met by a mysterious figure named Leland Gaunt, who gives her a "Stillness Cube" as compensation for the game's issues. This cube contains powerful and potentially dangerous items: an "Embryo of the Color from Outer Space" and the "Right Arm of Mr. Shiny," a Shoggoth Lord. These items, along with her previous experiences, suggest the game's world may be far more complex and perilous than initially assumed. Ane's stats have significantly increased, reflecting her in-game progression and the acquisition of new, powerful skills and titles. She then encounters a group of players who attempt to recruit her, but she uses her Shoggoth abilities to incapacitate them, further demonstrating her unique and formidable capabilities within the game.
