Under Story

Laurel Salter, a thirty-six-year-old mycologist from Wisconsin, arrives at McMurdo Station in Antarctica in October 2016, not as a scientist but as a kitchen steward. She has taken a leave of absence from her university position, sold her house, and fled to the bottom of the world after a devastating personal loss. On her first day, she notices a strange dome of light on the horizon, faintly pink and translucent. The phenomenon, which residents call the Arc, has baffled atmospheric scientists and drawn a team of physicists to investigate.

Laurel settles into McMurdo's communal rhythms alongside her roommates: Charlie Morrison, a graphic designer from Milwaukee, and Nita Choudhury, a marine biologist studying octopuses in her sixth Antarctic summer. She also befriends Louis Carroll, a British steward who has returned to the station seven times, and reconnects with Jules Javurek, her childhood neighbor who now serves as lead steward and has transitioned since she last knew him.

Through extended flashbacks, the novel traces the roots of Laurel's life. She grew up on her parents' organic apple orchard in rural Wisconsin, where her father, Pete, taught her that every organism in an ecosystem is interconnected. After Pete's sudden death from cardiac arrest during her freshman year of college, Laurel drifted until she attended a lecture by Gloria Albert, a mycology professor whose research on fungi and decomposition gave Laurel a new framework for understanding death. Gloria became her mentor, and Laurel joined the Rhizotron, Gloria's underground lab at the University Arboretum. There, Laurel designed an experiment demonstrating that the fungus Pisolithus microcarpus could learn and remember a maze's solution, suggesting a form of fungal intelligence.

She presented these findings at a conference in San Francisco, where she reunited with Eli Rosen, her high school crush, now a physicist at Stanford. Over dinner, Eli explained his Duoverse theory: The universe might have a mirror partner, an antiuniverse where time moves backward and antimatter reigns, the two sharing a single Big Bang. Despite intense mutual attraction, Eli was engaged to a colleague named Angela, and they parted without resolution. A year later, Eli took a visiting professorship in Madison and was single. They became lovers, and their son, Silas, was born in August 2006. They married in 2011.

Back in Antarctica, the team operating ANITA, a particle detector flown over the Arc, presents its findings to the station: The instrument has detected high-energy neutrinos traveling upward from the Arc's vicinity, particles whose inverted properties suggest a reversed arrow of time. Then, in February 2017, Eli himself arrives at McMurdo, recruited to study the anomaly. Over weeks of cautious reconnection, he reveals that the neutrinos' energy signature of 480 PeV matches a dark matter prediction he made years earlier. Laurel pushes further, suggesting the Arc is a portal to the antiuniverse. Eli resists but cannot entirely dismiss the idea.

The novel now discloses what drove Laurel to Antarctica. In August 2014, while vacationing at Lake Michigan for Silas's eighth birthday, Laurel walked into a cave to examine bioluminescent mushrooms while Eli went for a walk and Silas napped on the beach. When she returned, Silas was gone. She saw a hand in the water and swam desperately toward it, but the undertow overpowered her. Eli pulled her out, and Silas was never found. The marriage collapsed under blame and grief. They divorced.

Laurel proposes a plan: They will dive into the basin beneath the Arc, cross to the antiuniverse, and find a way to reach Silas. Eli calls the plan "unhinged" (141), but Laurel persuades him, insisting she has "nothing to lose" (154). After months of physical preparation, they execute their dive on October 8, 2017. Underwater, an octopus guides Laurel through a cloud of ink at the basin's center. When they surface, the sun is falling instead of rising. They have crossed into the antiuniverse.

At this world's McMurdo, they discover that doubles of everyone they know inhabit the station. Their counterparts appear to have departed deliberately, wiping their devices and clearing their belongings. Laurel confides in Nita Two, who is stunned but supportive. The group leaves Antarctica for Madison, where Laurel and Eli assume their doubles' professional identities.

Laurel gradually uncovers the antiuniverse's central biological inversion: Fungi compose life rather than decompose it. People are born old, composed underground by fungi, and grow younger over their lifetimes. An overtaker named Kenji Nakamura delivers the newly born and oversees the process. Eli proposes that if people here are born on the day they died in the original universe, Silas Two should appear on August 18, 2014, three years away. They decide to stay.

On the appointed day, the lake breaks open and Laurel sees a hand. This time, she and Eli swim together, connected by a rope, and pull Silas from the water. He is eight years old, wrinkled and blue-skinned, with a newborn's motor skills. Genetic testing confirms he is theirs. They raise Silas Two through reversed development; his first word, like Silas One's, is "light." But he is growing younger, losing height, vocabulary, and teeth. Meanwhile, Laurel works with Gloria Two, a brilliant young woman she recognizes as her mentor's counterpart, on an experiment tracking a white oak tree growing from the Michigan cave. After years of monitoring, they witness the Spark: the moment the tree achieves independent life, separating from the fungal network. Eli, searching for another portal, takes an Antarctic cruise with Laurel, but the basin is frozen and empty. An entropy detection device he built confirms they remain in the antiuniverse, not their home world. The portal is closed.

As Silas ages backward into infancy, Laurel undergoes a reverse childbirth at the cemetery's white building, experiencing a sacred connection as Silas's life force rejoins hers permanently. Afterward, Laurel and Eli separate to heal independently. From Kenji, Laurel learns that her doubles had a daughter, Celeste, an astronaut who died when Laurel Two miscalculated the window for the reverse-birth process. This tragedy drove the other couple to cross over, mirroring Laurel's own quest.

Years later, now teenagers in the antiuniverse's backward timeline, Laurel and Eli reunite. Using a placemaker device given to them at McMurdo, Laurel summons the Antarctic doubles of Nita, Louis, and Charlie to Wisconsin, where they join local friends in an effort to find a way home. A group dream yields cryptic clues leading Laurel to a hidden letter from her double and, in Gloria Two's guest wing, a gold pocket watch with copper filigree circuits and four clock faces. During a thundersnow storm, lightning activates the device. Laurel is pulled into the Void, a space between universes where stranded travelers drift. There she finds Olga and Ted, Gloria's parents, who vanished near Yosemite decades earlier. Olga repairs the watch, and Laurel tells them about their daughter's extraordinary life. Olga warns the watch may only work once more.

Laurel turns the repaired knob and lands in snow beside Eli, uncertain which universe they have reached but alive, together, and open to whatever comes next. The novel closes on a note of radical possibility: There could be another child, "a wavy-haired daughter who will ask them to tell her the story, from the beginning" (500).