If you think the holidays with your relatives were surreal, wait until you experience Christmas with the Cleves family.

They not only snipe and sulk, but also they hallucinate — and I don’t mean visions of sugarplums. Disembodied heads roll down hallways and coastlines crash through the ceiling of an English country house in “Winter,” the second installment in Ali Smith’s quartet of seasonal stand-alone novels.

Sisters Sophia and Iris are children of the 1950s whose upbringing was colored by their parents’ experience during World War II.

Sophia grows up to become a single mother and a successful politically conservative entrepreneur.

Her older sister Iris joins the counterculture, leading protests, living in communes and possibly planting pipe bombs.

Estranged for decades, the squabbling sisters accuse one another of being deluded, mad, self-deceiving.

They have entirely different perceptions of their mum and dad and just about everything else. As the author notes, they have “their visions and their divisions.”

Sophia’s son Arthur is a narcissistic millennial who spends his days online, busting copyright infringers and fabricating “general sorts of invented shared memories” to post on his blog, @rtinnature.

But this special snowflake is in meltdown now that his girlfriend has dumped him, destroyed his laptop and highjacked his Twitter account. Rather than admit the reality of his situation, Art has hired the mysterious stranger Lux to impersonate his ex for the duration of the holiday.

Over a period of three days, these characters do what most families do and in doing so, bond with one another. Except for the psychotic breaks, it’s all perfectly normal.

The familial circumstances exist mainly to underscore the relative-ity of perception and belief, which is the book’s overriding theme. And, as is the case with family, readers are likely to feel a combination of affection and annoyance.

It’s impossible, for instance, not to admire the author’s ability to cultivate so much from a sterile season. But then, this is not the bleak midwinter of popular imagination, filled with bracing winds and purifying white stillness.

It is a gray “half-season,” a “post-millennial global warming” winter, mild enough for Lux to sleep comfortably on a bed of hay in the barn.

It’s the political climate that delivers the shivers, with Twitter storms, fake news and polar-izing issues at every turn. “It’s like walking in a blizzard all the time, just trying to get to what’s really happening beyond the noise and hype,” writes Ms. Smith, adding short chapters on recent real-world events to drive the point home.

Things are equally confusing for readers confronted with multiple suggestions for the motivations and visions of various characters.

Can they be attributed to too much wine? Too little food? Pesticides? Parental neglect? Suppressed memories? Repressed feelings?

Also swirling throughout the book are historical, literary, linguistic, artistic, mythological and religious references that grow overwhelming. “Multilayered” doesn’t even begin to cover it.

Character names are a case in point: Art is Art, except when he’s the legendary king Arthur; Sophia is “wisdom”; Lux is both “light” and a flaky product that scrubs things clean; and Iris is not only a flower and a rainbow goddess connecting heaven and earth, but also an acronym for the EPA database of toxic chemicals found in the environment and a controversial hypothesis regarding climate change.

And that’s just the tip of the iceberg.

Certain readers may resent Ms. Smith’s erudition, but those who identify as “clever clogs egghead smartypants” (as one character does) will gleefully embrace each allusion — until they realize they’re being snowed.

For the “fact” is, any one of the proffered explanations is as viable as any other, depending on one’s perspective. And because reality is what one chooses to believe, individuals will select the meaning that appeals to them.

“Into whose myth do we choose to buy?” the novel asks. “That’s what it’s all about. … What we believe is happening.”

Despite some of the more dire forecasts issued throughout the book, it seems to be weighted toward optimism. When a busload of birdwatchers pulls into the Cleves driveway on Boxing Day — following alleged sightings of a rare North American bird whose fictitious appearance in the UK was first reported in a malicious tweet by Art’s former girlfriend — they bring with them gifts of infectious faith, hope and good cheer.

The world may not be as cold as it once was, but it sure is dark. As long as we’re picking and choosing, optimism seems like a good choice.

Sandra Levis is a freelance writer and editor who lives in Point Breeze.

First Published: January 21, 2018, 5:00 a.m.