Shortly after I first began working at the British Library, I knew that I’d use my newfound access to 150 million media objects—magazine articles, oral history recordings and books, many of them rare—to get my hands on The Pepsi-Cola Addict, the sole novel by June Allison Gibbons, one half of the infamous “silent twins.” Connoisseurs of weird crime stories—or weird twin stories, for that matter, or the surprisingly rich subgenre of weird twin crime stories—can do no better than the bizarre, tragic yarn of the Gibbons twins.

Born on an RAF base to Barbadian immigrant parents in 1963, June and Jennifer, the third and fourth of what would eventually be five children, were noticeably different from their peers almost from birth. The infants fought to be breast-fed simultaneously. When they entered school in a Welsh village at four years old, they were reticent, but by eight, though they read and wrote proficiently, they had simply stopped speaking—to their teachers, classmates, and even their parents, beyond a few nonverbal noises and monosyllabic answers to routine questions.

Shyness, writes journalist Marjorie Wallace in her definitive book The Silent Twins, became the “charitable explanation” for their speechlessness, though many felt something more sinister was going on. The most common theory was that Jennifer, the younger by ten minutes and widely considered the less intelligent, was controlling her sister. “Jennifer was stopping June,” a therapist who treated the girls told Wallace. “I watched and could barely detect the slightest eye movement, but I know she was stopping June.” One teacher even went so far as to label Jennifer “evil.” June and Jennifer did speak to each other in what sounded like rapid-fire gibberish, but they would cease even that if anyone else entered the room. Eventually, a specialist in elective mutism determined, after slowing down audio recordings she had made of the their discourse, that the twins were speaking regular English but so quickly that it was unrecognizable to the average listener.

It’s not uncommon for twins to develop their own language; it is rare that they become as fiercely codependent as the Gibbons girls did. They moved in languid tandem. The only physical activity they seemed to perform with any ease was horseback riding, but if one fell off, the other would immediately follow suit. When they were bullied—which, as the only black kids in town, they likely would have been even had they not behaved so oddly—they huddled together, with their arms on each other’s shoulders, as if to erect a little fortress of two. An attempt by the special high school they attended to separate them went disastrously: June, who was temporarily moved to a psychiatric hospital while her sister remained at home, stopped eating and moving, even to wipe away the steady stream of tears that ran down her face.

After the girls left school as 16—as they were hopelessly unemployable, they were advised to go straight on Britain’s version of disability—they developed an even more elaborative fantasy world populated by dolls, who they casted as American teenagers who ate Big Macs, rode Greyhound Buses and occasionally robbed convenience stores. Through the dolls, the twins developed a taste for elaborate storytelling, and soon they were sending in for creative writing correspondence courses. Writing became an all-consuming passion for the twins, who stayed awake until the wee hours, ensconced in their bedroom, tapping their short stories about American teens running wild on an old typewriter, which they undoubtedly took turns using. They were meticulous in their study of literature, dogged in their attempts to get their work published.

The analysis is easy: feeling ill-equipped to communicate directly with others using their voices, the girls poured themselves into their art in hopes the world would see its merit and reach an arm back to them. It’s a desperate impulse any writer can sympathize with. Over the course of their lives, they wrote dozens of short stories and a handful of novellas between them, including June’s The Pepsi Cola Addict, published originally in 1982 by British vanity press New Horizons. (She paid around 980 GBP, in installments of 80 pounds a month; Jennifer contributed from her welfare check.) At present, it is the only accessible work authored by either Gibbons twin.

And that’s saying a lot: The Pepsi Cola Addict is unavailable for purchase full stop these days, and apparently fewer than five libraries in the world have a copy. On GoodReads, 730 people have added it as “to read” since it was first listed on the site in 2007. Only 26 purport to have seen it, a few of them by snagging a photocopy. “Oh my god, I cannot believe I have a copy of this book,” writes a BBC radio producer. One pissed commenter shot back, “Stop telling us how much you loved reading the book and put a copy online! Please?” Flouting copyright laws, a few readers who managed to track down the book have scanned the pages, and sent them out into the world as if distributing samizdats. I feel almost a little bad at not having suffered more for my prize. I first heard about it in a 2007 Guardian article, about an opera (the second of two) based on the life of the twins; occasionally over the years, I did a cursory search for it, but the longing to read their works wasn’t something that kept me up at night. And then I found myself in Humanities One, holding a rather shoddily constructed copy of my very own.

So what’s it like? In a sense, The Pepsi Cola Addict conforms to the basic addiction narrative: dependence, followed by rock bottom, but ending on a cautionary note, rather than a promise of redemption. A 14-year-old student at “Malibu State School,” Preston Wildey King is—you guessed it—completely hooked on Pepsi Cola, which he has nicknamed “the high life.” (The champagne of soda pops!) Like any user, he drowns out his feelings with his drug of choice, and oh, does he have a lot to feel about. His dad is dead, for one thing, and his sister’s a mean slut. Mostly, though, his troubles are romantic: he is still painfully in love with his coy ex Peggy, a “wholesome cheerleader” who dumped him because of his nasty soda habit, while Peggy’s little sister, Preston’s best guy friend Ryan and Preston’s math teacher, to whom he loses his virginity, are all in love with him (but he can’t blame them, because he understands he is “attractive to everybody he [comes] into contact with.”)

At the beginning of the book, Preston’s up to 300 cans of Pepsi a day—that’s 45,000 calories and 12,300 grams of sugar, if you’re counting. He draws cans of Pepsi in art class—that is, when he’s not sneaking out of the classroom to quench his thirst. He loses his temper when Peggy dares to buy him Coca-Cola instead of Pepsi, as if he were a dope fiend whose dealer switched his black tar heroin with hash. He, perhaps predictably, dreams about Pepsi. At one point, he considers suicide, but Ryan talks him out of it. “That’s the easy way out Preston, and as the Indians say, any time’s as good as today to die.”

A die-hard Americanophile, Gibbons chose to set the story in a Malibu that would be beyond recognition to most Americans. Instead of a star-studded enclave, this Malibu is a place of down-and-out young hooligans, who speak, as Ryan does, almost like the cowboy in The Big Lebowski and engage in the occasional street skirmish on the “grey sidewalks” infested with rats that feast on uncollected garbage. The King family lives in a tenement, which is like saying a character lives in a Spanish villa in Siberia, and the neighborhood is home to a state hospital. Not all of it is comically off base: the kids do a lot of hanging out on the beach, and Gibbons spends a lot of time describing the waves of the “cerulean” sea, the breezes that cut through the air, the seagulls flying overhead, their wings flapping “like dried paper.” Much of the language is transcendently, uncannily strange—not completely nonsensical, but not elegant or meticulous either. In Gibbons’ hands, an awkward pause becomes an “elaborate silence,” and his teacher’s breasts are “cloche-shaped.” A supermarket is described as having a “turbulent” atmosphere, while a tense moment is observed from the point of view of the King home: “The apartment held its breath.” Gibbons has a tendency to describe characters’ emotional states as if alien forces that arise to visibility of their own accord. The characters, as a result, often come across as possessed. Their feelings “rouse” and expressions flit across faces like tics. “A fraternizing smile came over his lips,” Gibbons writes, or: “He felt penitence rise in him.”

One of the best parts of reading the book, though, is listening to Gibbons try to mimic American jive (it’s unclear exactly when the story is supposed to take place, although the bus full of “beatniks” that passes through early on suggests the 60s or 70s.) When Preston’s friend Ryan wants to ask what’s wrong, he instead queries, “Hey what fazes you?” Later on, someone chides, “Listen, don’t get nifty with me.” But my all-time favorite has to be when Peggy sarcastically tosses a compliment at Preston: “Maybe you’re the best thing since blueberry muffins,” she says.

I’ll spoil the ending, because it’s unlikely you’ll manage to get your hands on the book: Preston finally caves to pressure from a posse of boys, including Ryan and Ryan’s older brother, to rob a local convenience store, but he bungles the operation when he decides to stop mid-heist to chug a few cans of Pepsi. For his crime, he does time in a juvenile prison, and when he’s released, his whole world rapidly crumbles.

First the Mary Kay Letourneau in his life picks up and moves to Europe with her architect husband, Leif. Then, Ryan and Ryan’s older brother rob a bank and kill Peggy’s dad, a cop, in the process. When they try to make it to Mexico in a stolen green beetle, the police stop them, and Ryan is killed in the ensuing showdown. Meanwhile, Peggy’s family, surrounded by sad memories in rough-and-tumble Malibu, decides to relocate to San Francisco, which devastates young Preston. He takes a bottle of his mother’s barbiturates—washed down with Pepsi Cola—and passes out just as Peggy calls to tell him they’ve decided not to move.

The book ends enigmatically: just below Preston’s apartment building, a trio of young boys play kick-the-can with an empty Pepsi. The smallest boy kicks it the furthest, causing the last bit of liquid within to dribble onto the street. The boy runs over, dips his finger in it, and licks off the syrupy fluid. “I love Pepsi-Cola!” he declares. Is Pepsi to blame for poor Preston’s calamitous life? Is this little boy doomed to become, like our lustful enfant terrible Preston, a hopeless high fructose corn syrup addict, willing to steal for his habit? Has this all been one big PSA on behalf of the American Diabetes Association? These questions, and many others, must go unanswered.

As a character, Preston is the physical embodiment of many things June Gibbons aspired to be: white, American, irresistibly beautiful, male (June had written in her diaries about the “strange feeling I was a boy under all my female assets.”) But in other ways, they were just the same. Like Preston, June, along with her sister Jennifer, found herself a petty criminal in her teenage years.

When the literary world ignored them, the twins began to dabble in routine teenage rebellion—promiscuity, shoplifting, drinking and huffing glue—but eventually graduated to breaking and entering. “Why do this?” June wrote in her diary. “Nothing else to do. No friend. Nothing to fill in the cold hour.” For five weeks in late 1981, the girls went on a breaking and entering spree, culminating in their attempt to set fire to a building on a local technical college campus. They were caught and remanded to infamous psychiatric hospital Broadmoor for an indefinite period of time, the draconian sentence justified by their array of undecipherable psychiatric symptoms more than their crimes, which were basically victim-less. They stayed in Broadmoor for over a decade.

The day they were set to be moved to a lower-security facility nearer to their family home in Wales, Jennifer, then 29, died suddenly of an inflammation of the heart. Marjorie Wallace says that in the weeks leading up to her death, the twins had agreed that one should die in order to allow the other to live freely, though they had argued vehemently over who should go first. No drugs were found in Jennifer’s system, nor was there any sign of foul play or history of cardiac problems. June was eventually released and moved back to the small town in Wales where she had been arrested as waifish 18-year-old. She has never published another novel, which I hope means she can speak freely to those around her, and be heard.