In 2007, after the death of his grandfather, Sequoia Nagamatsu flew off to Japan, where he had never been, to teach English and to grieve. It was there that he started writing.

"My grandfather's death had a profound impact on me," Nagamatsu said in a recent interview from his home in Minneapolis. "I wasn't really able to say goodbye."

In Japan, he was surrounded by reminders of his grief.

"Japan is a country that is actively and increasingly dealing with what to do with the elderly population in terms of space and financial realities," he said. "So there are funerary skyscrapers, nontraditional ways that Japanese families are starting to embrace. I was doing that exploration as well because it fascinated me. I was also thinking about my grandfather.

"We're not used to talking about death and mortality. It's kind of a taboo subject, especially in the West."

The individual stories that he began writing there more than 10 years ago have become his powerful debut novel, "How High We Go in the Dark," which Nagamatsu will launch at Moon Palace Books in Minneapolis on Jan. 18. But while he was in Japan, alone and isolated in a country where he barely understood the language, "I didn't think of this as a novel at all. I was still deciding whether or not I would call myself a writer."

Climate change and plague

Nagamatsu, who teaches at St. Olaf College in Northfield, lives in Minneapolis with his wife, writer Cole Nagamatsu, in a house they bought during the height of the real estate boom. There was stiff competition, but the couple won the sellers over with an eloquent letter about their hopes to write books there and to turn a closet into a cozy nook for books.

Neither is a native Minnesotan — Cole is from Philadelphia, and Sequoia was born in Southern California. He grew up on the Hawaiian island of Oahu and moved to the San Francisco Bay Area at age 12.

The two met in grad school in Illinois, and when Nagamatsu moved away to teach, they stayed in touch by jointly editing Psychopomp Magazine, a literary journal they founded to publish what he calls "weird things."

"How High We Go in the Dark" is definitely a weird thing — weirdly wonderful and weirdly powerful, a book of speculative fiction so close to real life that its heart-stopping events feel almost inevitable.

The novel opens at a time in the near future when scientists, probing the permafrost of Siberia — thawing due to climate change — inadvertently release an ancient, powerful virus that swiftly traverses the planet.

Subsequent chapters focus both on grief and on hope. As millions die, including children, people find a way to give them a good death; to honor their memories through holograms, robot dogs and other devices; to save lives through genetically modifying pigs for organ transplantation, and, eventually, to preserve the human race by blasting off in a rocket to find a new world.

The stories can be piercingly sad, but are dotted with humor. "Humor was an important thing for me," Nagamatsu said. "I wanted to make sure there was some hope in each chapter, but also that there were some nods at lighter moments. I didn't want it to be a 24/7 grief parade.

"When you're talking about a tragic event or having lost somebody, you're going to cry but you're also going to laugh. I wanted to acknowledge that the full spectrum of emotions is going to be there."

"How High We Go in the Dark" has garnered effusive pre-publication reviews, and its publisher, William Morrow, announced an initial print run of 100,000 — unusual for a debut novel.

"Our Goodreads numbers are kind of wild," Nagamatsu said. "Unexpectedly so. More than 40,000 adds on Goodreads. The buzz is happening and it's really exciting."

Grounded in research

Nagamatsu's interest in Dystopian literature "goes back to the shows and novels that I grew up loving. 'Star Trek' — at its heart it was a very forward-thinking, original series. It tackled issues of race, of class, and some of my favorite episodes were deeply philosophical thinking about identity, what makes a human a human."

The show, he said, "helped me embrace narratives where, yes, there is the cool science fictional conceit — warp drives or whatever it may be — but that was never really the point. The point was using that as a way of attracting a dialogue that might be difficult to have in real life."

Nagamatsu devotes a lot of time to research, grounding his speculative fiction in fact. In one story, he mentions the black foliage on a distant planet, and a Goodreads reader noted that was believable for the kind of star that planet had, a red dwarf star. "So the way that the plants might appear to our eyes would be a darker color," Nagamatsu said. "That's the kind of thing I spent a lot of time researching and it's just one line. If people are science-y, they will appreciate it."

Early iterations of the novel didn't mention a plague, but that changed in 2014, when Nagamatsu read an article in the Atlantic about scientists finding and reviving ancient viruses frozen in the Siberian ice.

"Scientists being scientists, they're well-intentioned and they're prodding at it and trying to reactivate certain things," Nagamatsu said. "I love science, but my knee-jerk reaction was 'Have you never seen a horror movie? Do you not know what could happen?' "

Nagamatsu knew, and an unleashed plague eventually became a theme of the book.

Early in 2020 he and his agent were about to send the manuscript to publishers when COVID-19 hit. To publish a novel about a deadly worldwide plague during a worldwide pandemic seemed problematic, but after discussion, they went ahead.

The novel landed with William Morrow in a two-book deal. (The second novel, "Girl Zero," is due out in 2024. )"How High We Go in the Dark" is dedicated to another member of his family who died — his father, Craig Nagamatsu, who passed away while he was working on the book.

"We had kind of an estranged relationship," he said. "I think it was an important moment for me, working on this novel at that time. It did help me process my emotions.

"It kept me afloat during the pandemic. It was definitely an important part of my life. When not a lot of other things were going right in the world, there was this book."

How High We Go in the Dark

By: Sequoia Nagamatsu.

Publisher: William Morrow, 292 pages, $27.99.

Hybrid event: In conversation with Kawai Strong Washburn, 7 p.m. Jan. 18, Moon Palace Books, in person and livestreamed on Instagram @MoonPalaceBooks.