ublic Access Afterworld is the first novel by Jane Schoenbrun, director of cult-hit horror film I Saw the TV Glow and the more recent Teenage Sex and Death at Camp Miasma; movies in which screens are a permeable barrier and people are menaced by the uncanny realms that lurk behind them. Here the main character is Bethany Peters, a young trans woman working as a content moderator at a YouTube-like company called GlobalVill. Her job is to watch "offensive, illegal, disturbing videos that have no place on the internet" and press a red button to remove those that violate the code of conduct. One night she sees a video posted by someone with the username JulesPublicAccessAfterworld, a visibly malnourished non-binary kid who reminds Bethany of herself "before her stay in hospital, and everything that happened to her there". The kid says to camera, "If you're watching this, David Sawyer, this is for you," then takes out a razor blade and draws it down their arm. Soon Bethany is off on a quest to save them, in the course of which she will learn that she herself is one of "the crooked", people destined to vanish into Public Access Afterworld, the world behind the TV screen.

There are several other strands to the novel. A nameless patient at the Saint Thomas Youth Rehabilitation Center tells us about a fellow inmate "going by the name David Sawyer" who spends every night narrating a TV programme about a character called Bethany Peters. We meet David again as a lonely teenager glimpsing terrifying images in television static; then again as the cult leader and suspected serial killer to whom Jules and other aspiring "crooked" people dedicate their self-harm videos. We also go to Los Alamos in the final days of the Manhattan Project, where a troubled scientist's wife has begun to suspect her husband of making something worse than nuclear bombs. In one bravura section we meet Chimotera, the mad scientist/monster of a Lon Chaney-era horror franchise, who is brought back to life in different avatars across successive reboots, and slowly comes to understand and resent his true nature. Schoenbrun ingeniously unites these strands in an ending that manages to be uplifting and nihilistic at the same time.

A standout feature of this novel is its centring of trans experience. This seems natural, given Schoenbrun's gender identity as non-binary and transfeminine; but it also feels natural in the unfolding of the plot. We hardly need to be told how our Final Girl, Bethany, came to be such a canny survivor, or why she's so prepared to find herself the focus of other people's sick obsessions. The most memorable character, though, might be the cult acolyte Jules, a crooked person who is both frightening and strangely moving. Abused by their parents and bullied by peers, they've become dependent on drugs, incapable of forming relationships, and enraged at their failure to matter to anyone. In their goth ghost makeup, they embody the archetype haunting almost every ghost narrative: the traumatised victim of society's cruelty who has returned to exact vengeance.

Schoenbrun is an internet native, who started out writing in fan-fiction forums, and Public Access Afterworld has a casual, internetty tone, even when dealing with its darkest material. This novel fits into a contemporary school of cool, self-aware horror in books and on screen that is at once high-art and kitsch, moving seamlessly from cosmic terror to moody introspection to fan-friendly jokes. Think Widow's Bay or Chuck Tingle's Bury Your Gays or any of Schoenbrun's own films. At one point, the narrator says to the monster Chimotera: "You eat vital organs when really you're just eating your feelings." Occasionally a character will pause to marvel at how far-fetched the plot has become. It does get a little far-fetched, and the world-building doesn't always bear close inspection, but the knowing voice ensures the reader is always in on the joke. The informality of the tone is part of the appeal, but it can get a little sloppy. Here, for instance, is a description of the opening sequence of a TV show about werewolves and vampires warring in a dystopian United States: "The London Symphony Orchestra conducts, soundtracking our propulsive opening credit sequence whisking viewers over a CGI map of Second America." However, even a sentence like this has a certain pace and charisma, and it gets the job done.

In the treatment of their core theme – the relationship between the attention economy and its victims – Schoenbrun is wonderfully brutal, passionate and astute. They powerfully draw out the horror of screen culture, making us feel how, in some way, the ugliest content on YouTube inhabits the same nightmare subreality as the catchphrases and laughtrack of an 80s sitcom. They also capture our perverse longing to enter that world, to leave human life and become the story: to flee to the other side of the screen. The nameless patient at the Saint Thomas Youth Rehabilitation Center says: "They don't give people like us the Sunday night-time slot on HBO. They put us in hospitals. They send us to hell." Public Access Afterworld shows us that hell, a locked psych ward and the primetime slot on HBO can all be the same place.

Public Access Afterworld by Jane Schoenbrun is published by Sceptre (£20). To support the Guardian, order your copy at guardianbookshop.com. Delivery charges may apply.