Garrett works his shift at the airport, where he loads and unloads luggage for Maverick Air. Afterward, he drives to his father’s house, which previously belonged to Garrett’s grandparents. His 57-year-old father is dying of pulmonary fibrosis. His father came out as gay to Garrett’s mother when Garrett was a teenager, ending their marriage.

As they eat dinner and drink beer, Garrett tells his father about meeting Charlie’s fiancée and agreeing to officiate the couple’s wedding, despite Garrett’s disapproval of the institution of marriage. His father tells Garrett that he is worried about him, referencing the death of a friend of Garrett’s and Garrett’s subsequent hospitalization and then relocation from Los Angeles, California, to Montana. Garrett recalls being diagnosed with depressive psychosis. Now medicated, he is considered stable; Garrett notes that he continues to have occasional episodes.

Two weeks pass, and Cece finishes nearly all the wedding planning. Garrett has even accompanied her on trips to search thrift stores for vintage china for the reception dinner.

Cece agrees to hike with Garrett in Glacier National Park, and he picks her up promptly at seven o’clock in the morning. During the drive, Cece recalls her mother’s death from brain cancer when Cece was 17. She and Garrett discuss how unalike Cece and Charlie are, according to Garrett, and Cece tells Garrett about her dropping out of medical school while Charlie went on to be a cardiac anesthesiologist. Garrett inadvertently reveals his disapproval of marriage, and Cece challenges him. They argue, and Cece wonders if asking Garrett to be the officiant was a bad idea.

They arrive at the park and set out, though Cece does not reveal that she is afraid of heights. Garrett complains about the ways that human presence is destroying the natural landscape. When they encounter a mountain goat on a narrow path up the mountain, Cece panics, allowing her fear of heights to overtake her. Garrett is able to shoo the goat away and guides Cece by hand down the mountain. She feels surprisingly calmed by this.

After Garrett brings Cece back to the Margolis cottage, Cece invites him inside to sample the wines that she is choosing for the wedding. He keeps expecting her to ask him to leave at any moment, but instead, Cece keeps pouring wine. When she heads upstairs to talk to Charlie on the phone, Garrett sneaks out. From inside of his truck, he can see Cece through the upstairs window, watching him.

A week before the wedding, the Margolises arrive—Charlie, his parents, and his brothers fly in from various parts of California. All the wedding details have been taken care of, yet Charlie senses that Cece is tense. She pores over her laptop, searching for “welcome bag” favors for the guests, even though she and Charlie had agreed that such details are excessive and unnecessary. Charlie’s father is confined to a bedroom—ill with what everyone suspects is food poisoning but later turns out to be norovirus.

Charlie is eager to see Garrett, but Garrett does not return any of Charlie’s phone calls. Charlie thinks about Garrett’s hospitalization in San Francisco, California; Charlie was unable to visit because he was studying for the board exams. When the doorbell rings, Charlie hopes it is Garrett but finds the wedding photographer instead.

The photographer situates Cece and Charlie at various places around the property, testing the light. He points to a bald eagle in a nearby tree, and the three watch as it flies into a nest filled with baby ospreys. Cece begins to panic, and Charlie grabs a shotgun that is kept nearby to scare birds away from the garden. He fires a shot straight into the air and successfully scares off the eagle. Neighbors, however, call the police when they hear the gunshot; the police arrive and warn Charlie about the fines and penalties for harming a bald eagle.

Garrett wakes up from a dream in which he is kissing Cece. It is the night of Charlie’s bachelor party, and Garrett is late, having worked a shift at the airport that ended at three o’clock in the morning.

He arrives at the Margolis cabin to find a group of old friends and Charlie’s brothers gathered outside but no sign of Charlie. Garrett accepts a beer and tries to joke with the other men, but he is certain that he has made a mistake by coming. He enters the house in search of Charlie and finds him sitting on the roof just outside a bedroom, smoking Marlboros. Charlie explains that he does not want to be caught smoking. He tells Garrett about how tense Cece has been since he has arrived, and Garrett tries to assure him that it is merely wedding nerves.

Meanwhile, Cece is camping nearby with girlfriends, including Paige, her high school best friend. While the two struggle to set up the tent, Cece asks Paige about marriage, unable to put her finger on the cause of her uneasy feeling. Charlie’s mother has also become ill with norovirus, and she and Charlie’s father are quarantining at a nearby hotel. Paige assures Cece that everything will be fine in time for the wedding.

At the end of the night, the men strip off their clothing and jump into the lake, overtaken by the effects of drugs and alcohol. They even convince Garrett to join them, and for a while, he feels close to his friends once again. Suddenly, a car carrying Cece and her friends appears, having returned early from the camping trip.

This chapter consists of an email that Garrett sends to Cece in the middle of the night. In it, he admits that he is drunk but reveals many details of his life—he hints at being present when his friend Elias died and blames himself for the death (though Garrett does not reveal anything about the circumstances of Elias’s death). He talks about his passion for nature and the environment as well as his past suicide attempt, in which he ingested phenobarbital and was then committed to a psychiatric hospital. He repeatedly speaks of how he considers himself disconnected from other people and life in general. He insists that being around Cece has made him remember what it is like to be happy.

This chapter consists of a single, brief email from Garrett to Cece in which he asks her to delete the previous email, begging her not to read it.

At work, Garrett worries about the emails sent to Cece, obsessively checking to see if she may have replied. After his shift, he drives to his father’s house.

His father tells him that he ran into Charlie and Cece at the grocery store. Garrett tries to shut the conversation down, but his father insists on telling him about a boy he once had a romantic fling with in high school. When his father begins coughing, he goes into the house for water. When he does not return, Garrett enters the house and finds him lying on the floor.

Cece lies awake in bed on the night before the wedding, with Charlie snoring beside her. Earlier, they held a wedding rehearsal dinner, with one of Charlie’s brothers giving a notable toast about Cece’s ability to curb Charlie’s inflated ego. Garrett was not in attendance due to his father being hospitalized; he assured the couple, however, that he would still officiate the ceremony. Charlie apologized to Cece about asking Garrett to perform this role, but Cece insisted that it no longer matters. She assured Charlie that she had returned to calm, noting that she had not even checked her email in two days.

Garrett sits beside his father’s hospital bed. His father has suffered a stroke, but because Garrett was able to get him to the hospital quickly—even notifying the emergency room as he drove—his prognosis is good. When his father awakens, the two try to make jokes with one another. Garrett describes a funny incident that happened when he was skiing as a child, but his father does not remember the anecdote. Garrett thinks about how there is no one but him who will visit his father in the hospital.

The narrative shifts back in time to the day when Charlie first meets Garrett, during their freshman year of college. They are students in the same philosophy class, and they strike up a conversation after class one day when Charlie notices that a coveted girl on campus—Sabina Gonzales—is talking to Garrett. Charlie is pleased to discover that Garrett is from Missoula, Montana. They horse around, and Charlie slips on the ice, sliding down a small hill and nearly into oncoming traffic. Garrett dives to push Charlie out of the way and then takes him to the emergency room for medical care.

As they are exiting the hospital—with Charlie’s arm in a sling—they encounter a sophomore named Elias. Elias has a large bruise on his neck from a fight with his roommate over dirty dishes. Garrett sneaks Elias into the dining hall on campus, and from then on, the three are great friends.

The narrative jumps forward to a time when Charlie and Garrett are sophomores. Along with Elias, they dress up as speedbumps for a campus Halloween party. Sabina attends the party, too, and as the boys walk drunkenly through campus late at night afterward, Elias yells out her name. A student yells at him from a dorm window, telling Elias to shut up, and then Sabina herself appears at the window—the yelling student is her boyfriend. At the end of the night, Charlie and Garrett share a cigarette and promise to be friends forever.

The narrative shifts forward in time again—this time, Charlie and Garrett are college juniors, and Elias a senior. Elias is dating Sabina, and the three friends are inseparable. They meet in Colorado during winter break, where they hike to a remote shanty for a skiing adventure. Charlie feels alive, thrilled to be in the remote landscape with his best friends. On the first night after a day of skiing, Elias reveals that he and Sabina are talking about marriage.

The next day, Garrett leads them out onto a pristine area of untouched snow. They ski, but then Elias is suddenly trapped beneath an avalanche. Garrett digs and digs, desperate to reach Elias.

Cece and Charlie’s wedding day arrives, but many of the guests and wedding party have contracted norovirus. Garrett arrives at the Margolis cottage, his shirt missing a button and his mind alternating between its focus on his hospitalized father and the emails he sent to Cece. He helps Charlie’s father—who appears to be drunk—set up some chairs and then makes his way into the house in search of a safety pin to fix his shirt. Inside, he bumps into Charlie, who fears that he is also coming down with norovirus. Garrett tries to lift his spirits.

In search of a bathroom, Garrett mistakenly enters a bedroom where bridesmaids are tending to a crying Cece. When Garrett approaches her, she hisses at him.