Adam Silvera has always been preoccupied with his own mortality. He recalls holding his infant goddaughter when he was suddenly struck with an irrational terror that someone was about to break in and kill them both. And then he thought, but what if we got a warning—advance notice of our impending demise. “For me, writing always begins with this what if question,” he says.

That question, what if we got a warning on the day we were going to die, became the premise of Silvera’s new novel, They Both Die at the End. Just after midnight on Sept. 5, Mateo and Rufus each get a call from Death-Cast informing them that they’ll die in the next 24 hours. The two teens meet through the Last Friend app (which is exactly what it sounds like) and set out to help each other make the most of their last day.

The novel is mostly unconcerned with the mechanics of Death-Cast—though supposedly scientific, it functions more like magic—and focuses instead on how the innovation affects the people living in this world. “I love the 15 minutes into the future stories,” Silvera says. “I love this whole thing where it’s like, ‘let’s change this one little thing about society and see the way that everything completely evolves and erupts.’ ” We see not only Mateo’s and Rufus’ perspectives, but also those of other characters, from Death-Cast employees to a journalist convinced her death call was a hoax, as they navigate a world where death is just slightly less sudden.

Nevertheless, Mateo and Rufus’ relationship forms the core of the novel. They meet, they fall in love, and, as the title makes clear, they die. Silvera, at least, still finds their relationship uplifting. “The beauty is that you guys did meet, that you had this one day together instead of zero time at all, and I still think that’s very special,” he says. “At the end of the day, we all die, and that’s the brutal reality.”

Silvera admits that this is not a book for anyone looking for a cheerful read—after all, the ending is right there in the title. Nonetheless, he embraces that darkness and his reputation as a heartbreaker, because it’s important for readers to be able to see their own challenges and their own disappointments reflected in fiction. “I want to put characters out there who are going through difficult trials and are still able to find the beauty in their lives,” he says. “I want people to be able to find the light in the darkness.”

In fact, writing They Both Die at the End served as a kind of therapy for Silvera. Like Mateo, he would often obsess over the way things could go wrong, convinced that he would fall out of the roller coaster or that his plane would crash. “Writing this book has helped me break out of my own shell a little bit and sort of take it day by day,” he says. Were Death-Cast real, he insists that he would absolutely opt in to it.

At 27, Silvera is part of what he calls “the ‘Harry Potter made me a reader’ generation,” and consequently, he has immense respect for the power of young-adult fiction. Though he hopes to write all kinds of books in the future (including middle-grade, adult fiction, and graphic novels), YA will always be his first priority.

He started writing at 11, composing fan fiction set in his favorite fictional worlds, from the aforementioned Harry Potterto TV shows like Supernatural and Charmed. “It’s such a great exercise because I didn’t have to create characters from scratch or settings from scratch or magical systems from scratch. All I had to do was write,” he says. He even recommends writing fan fiction to young aspiring writers as a way to hone their craft and get in the habit of writing.

Silvera wrote his first novel, More Happy Than Not, when he was just 23 and still in the process of coming out. Part of the appeal of writing about teen characters was the chance to reimagine his own adolescence. “I get to sort of walk roads that I was too scared to walk myself as a kid,” he says.

Four years later, Silvera’s still exploring his sexuality, in both his life and his fiction. “Sexuality is just so fluid,” he says. “I mainly lately just say I’m a queer dude because gay doesn’t feel quite right anymore, and I’m still trying to see if bisexuality feels right for me.” Because of the bi-erasure he witnessed growing up in the South Bronx, where, at least for boys, bisexuality was just a step toward coming out as gay, it was important to Silvera that Rufus’ bisexuality was accepted and affirmed by those around him.

Writing about marginalized characters, Silvera takes the burden of representation seriously. “I’ve been privileged enough to hear from so many readers over the years about how much they needed my stories, the stories I put out there,” he says. “I didn’t think that I would write anything that mattered, and that sort of responsibility, I don’t take that lightly.” Beyond just the readers who see themselves in his stories, he hopes that They Both Die at the End’sunique premise can draw in readers who might not normally read a queer romance and inspire them to broaden their reading habits in the future.

YA readers (and critics and authors) can be a demanding group, with high standards for both sensitivity and narrative, and Silvera acknowledges that he’ll never write a book that pleases everyone. Yet despite recent controversies, Silvera believes YA’s online community does by far more good than harm. “I’ve met people in YA who have quite literally saved my life,” he says. When he was suicidal, it was fellow YA writers, many of whom he met online, who were first to reach out.

As for writers who might be worried about running afoul of those high standards? Silvera suggests writing whatever story speaks to you but treating all characters, regardless of race, gender, or orientation, with the same care. “If you have a character who’s just one-dimensional then you’re just doing a shitty job as an author, that’s what it comes down to,” he says. “It’s not that you’re a bad human, it’s just that you’re failing your story.”

Alex Heimbach is a writer and editor in California.