Bryan Washington’s debut novel, “Memorial,” opens with a comic premise: Mike and Ben are a young gay couple in Houston waiting for Mike’s mother to arrive from Japan. But as soon as she lands, Mike plans to fly off to Osaka to see his dad, leaving Ben to entertain his angry mom by himself.

“I’ve never met her,” Ben complains.

“True,” says Mike. “But I’ve already bought the ticket.”

This may feel like the contrived start of a zany meet-the-parents mix-up. But “Memorial” is a profoundly sensitive story about the rough boundaries of love in a multicultural society. In fact, no other novel I’ve read this year captures so gracefully the full palette of America. The range of cultures, races, generations and sexual identities contending with one another in these pages is not a woke argument; it’s the nature of modern family life fully realized.

Washington launched his extraordinary career last year with the publication of “Lot,” a collection of stories also set in Houston. It earned the author a 5 Under 35 honor from the National Book Foundation, several other awards and an endorsement from an enthusiastic reader named Barack Obama, who said “Lot” was one of his favorite books of the year.

The successful transition from short stories to novels is not guaranteed, but Washington, now all of 27 years old, didn’t merely shift to a longer structure; in the process, he’s also invented his own idiosyncratic form. “Memorial” unfolds as a series of isolated moments, many only a page long, some merely a single line. Told first from Ben’s perspective and then from Mike’s, these moments continually blend past and present, enacting each narrator’s confession as a kind of prose poem.

That easily could have fused into a great muddle or — worse — something self-consciously artsy. But Washington inhabits these two men so naturally that the sophistication of this form is rendered entirely invisible, and their narratives unspool as spontaneously and clearly as late-night conversation.

We hear from Ben first, trapped in a one-bedroom apartment with his boyfriend’s mother, Mitsuko. Their first morning together, Ben finds her taking over the kitchen. That’s fine with him — Mike always did all the cooking anyhow — but Mitsuko is engaged in some kind of passive-aggressive culinary battle. She’s angry at her son for abandoning her the moment she arrived in Houston, and she’s not thrilled with his new lover, either. “She doesn’t look up,” Ben says, “doesn’t even acknowledge that I’m around.” For many days, every effort he makes to engage her is met with silence or sarcasm.

Washington is so good with this comic awkwardness. Even when Mitsuko makes an effort to play nice, she can’t sustain it for more than a few seconds. Her every apparent concession is just another trap:

“I realize that this must be strange for you, too,” Mitsuko offers.

“No,” Ben says, “I’m fine.”

“So you’re a liar,” she says. “Your place is filthy, but it’ll work until Michael makes it back.”

After a few days of living together, her idea of striking up conversation is to say, “So, you’re black.”

As their contentious duet plays out, Ben’s narration draws us into the wider complexities of his life as a Black man who is HIV-positive. Rejected by his own family when that diagnosis made his sexual orientation impossible to ignore, Ben has grown wary and circumspect. Belated efforts by his family to reach out now strike as suspect and tardy. This is, among many things, a novel about the persistent supplications of parents, even parents who don’t know how to ask for love.

That theme is developed under more exigent circumstances in the novel’s second part, set in Japan. Though it might seem that Mike would fit in here, he doesn’t, which heightens his sense of alienation. He’s come to Osaka suddenly because his estranged father has only a few months to live. He hopes to reconnect while that’s still possible, but the old man displays no happiness whatsoever at seeing his son for the first time in 16 years. “I thought he’d hug me or grab my arm or punch me in the face, but none of that happened,” Mike says. His father just swears and asks how he plans to spend his time in Osaka.

“I flew here for you,” Mike says. “I came down here for you.”

“Which is fine,” his father says. “But you need a job. And I need extra hands. . . . We’ll spend more time together if you make yourself useful.”

Washington deftly distinguishes the voices of his two young narrators, but they share a resilient compassion for these older relatives who treat them with such exasperation and disdain. In a disposable society, “Memorial” is a testament to the permanence of filial connections, a clear-eyed acknowledgment that our relatives don’t always behave nicely, but they’re with us for life.

What becomes apparent, though, is that Mike and Ben may not be with each other for life. Sex had already started to substitute for affection, and the arrival of Mike’s mother and the precipitous decline of his father have interrupted a difficult conversation about what exactly Mike and Ben want from each other. Washington’s style — the accumulation of muted memories and remarks — perfectly reflects the flickers of insight and denial that a dying relationship emits. Trying to continue that conversation across the globe in a series of oblique text messages and emoji is futile. Even the touristy photos Mike and Ben exchange — reproduced in these pages — serve only to emphasize the alienating effect of substituting images for intimacy.

Mike’s mother finds her son’s constant reevaluation of his romantic situation obsessive. Back in her day, she claims, “One thing happened, and then another thing happened. We didn’t think about whether it would work or not. We just did it.” True or not, that’s not a philosophy anyone can pass on to introspective guys like Mike and Ben. But her larger point, about the need for acceptance, about faith in one’s ability to deal with whatever comes, resonates as this novel’s poignancy slowly builds.

“I guess that’s the thing,” Mike thinks. “We take our memories wherever we go, and what’s left are the ones that stick around, and that’s how we make a life.”

That’s how Washington makes a novel, too, as a series of attentive memories. Individually, few of them may seem significant, but when arranged with such lyrical care, they memorialize the lives of people who matter, people we love.

Ron Charles writes about books for The Washington Post and hosts TotallyHipVideoBookReview.com.

Memorial

By Bryan Washington

Riverhead. 320 pp. $27