Michael Cunningham's novel "Day" joins a fracturing Brooklyn family on April 5 in three years spanning the COVID-19 pandemic.

Isabel Walker is a hardworking magazine photo editor, unhappily married to Dan Byrne, once a minor rock musician who is now the on-call parent for their two children, Violet, 5, and Nathan, 10. The family occupies two floors of a brownstone, with Isabel's brother Robbie living in the attic. Robbie, a schoolteacher smarting from a breakup with a boyfriend, is the hub of this family wheel, the person who connects everyone and keeps them moving. Robbie is both Dan and Isabel's best friend, and the backup caregiver for the kids, whom he supports as only a favorite uncle can.

But the family balance cannot last. As "Day" opens, it's 2019 and the kids are growing too old to share a bedroom. The plan is for Robbie to find his own place so Nathan can move to the attic. Meanwhile, Isabel, who "loved her job until the day she didn't," is dissatisfied and everyone feels it. On the first April 5th, Cunningham captures the tension in the family as they contemplate the necessary, unimaginable breach to come.

The pandemic lockdown arrives as Cunningham skips ahead one year and finds Robbie marooned in Iceland and the other family members trapped in their apartment. Another year's leap leaves the family even further altered.

Cunningham — who has built a career on fiction that explores mortality, the passage of time and how the pressures of both alter intimate relationships — is the perfect writer to examine the pandemic. "Day" features themes familiar from Cunningham's Pulitzer Prize-winning "The Hours," including a mother who longs to escape her family, lives cut short by contagious disease, and a character named Wolfe/Woolf. But while "The Hours" circled around Virginia Woolf, in "Day" Wolfe is the name of an Instagram character invented by Robbie and Isabel, a grown-up form of sibling play in which they post photos that purport to display the idealistic life of a young pediatrician who is "fabulous and obtainable, a regular guy with the volume turned up a little."

The novel's structure mirrors the way momentous changes are announced on social media, through a sudden absence or a lurch ahead in time. "Day" also captures how time felt distorted during lockdown, with gaps in the continuum. Nathan thinks "he lives in an ongoing series of minutes that arrive and depart but are not quite fully connected to each other, so that a day is a rapid-fire progression of still photographs." The characters are locked in the patterns of their lives, locked in the repetition of their thought loops.

The novel's structure gives Cunningham an ideal template for his characteristic style, as he builds tension between characters, then cuts away without depicting confrontation or farewells, only anticipation and aftermath.

Cunningham remains a writer of extreme poise, with a penetrating intellect and a winsome sense of humor. His sentences make you want to bask, to take a nap in their sun. And "Day," like all his novels, invites readers to consider their own loves and losses.

Jenny Shank's story collection "Mixed Company" won the Colorado Book Award and her novel "The Ringer" won the High Plains Book Award.

Day

By: Michael Cunningham.

Publisher: Random House, 273 pages, $28.