Finley Hope graduates from Jackson High School, but the celebration highlights the awkwardness of her split family. Her father, Jason, and his wife, Marisol, wrangle their young children on one side while her mother, Catherine, stands apart in sunglasses, stiff and silent. Catherine left when Finley was four and works as a corporate staffing advisor who travels constantly; their relationship consists of a few obligatory visits Finley calls "Catherine's time." Finley's boyfriend, Colin Frisbee, comes from a close family. They have been together since junior year, when a fifty-states quiz gave Finley the nickname "Idaho" and launched their romance. Colin drew her into a social world of family dinners and game nights that made her feel she belonged. She even turned down her dream school, Pacchiana College, to follow him to the state university. On graduation night, she asks Colin if they will be okay. He deflects with a joke and never really answers.
The next morning, Catherine arrives looking unlike herself: plain T-shirt, dark circles under her eyes. Instead of New York, they are driving to the family's lakeside property, which Catherine calls "the Woods." Catherine's maiden name is Woods, and the house belongs jointly to her and her two younger sisters, Liz and Kasey. Finley knows almost nothing about this side of her family. On the drive, Liz calls twice, furious about Catherine's sudden arrival and accusing her of years of neglect.
The Woods is a white house on the shore of a lake, with a smaller cabin across the driveway. Liz, a real estate agent, is openly hostile. Kasey, the youngest sister, is quieter but conflicted. Clark, a Black teenager Kasey has raised as a surrogate son, mistakes them for lost tourists. The sisters begin sorting the house for sale. Liz is sentimental, Catherine is coldly efficient, and Kasey resents her years of absence. The Tides, a resort buying up surrounding land, plans to raze the property.
Colin video-calls Finley from his Disney cruise and breaks up with her, saying he wants to experience a wider world. Finley retreats to her room in tears. That evening, Ben Cross, a curly-haired cook at the Egg, a small restaurant near the Woods, finds her in the kitchen and offers her grapes as awkward sympathy. Later, Finley sees Colin on a group video chat beside a girl who looks just like her and throws her phone into the lake.
Phoneless the next morning, Finley walks to the Egg and is drawn into the breakfast rush. She learns the ordering shorthand, buses tables, and runs food, discovering a talent for the restaurant's chaotic rhythm. Kasey pays her in cash. The work is the first relief she has felt since the breakup.
Late one night, the printer spits out medical documents bearing Catherine's name. The words "lumpectomy," "mastectomy," and "chemotherapy" stun Finley. She calls her father, who advises against bringing it up, but confronts Catherine anyway. Catherine opens up: She found the lump the previous summer, ignored it for months, and recently learned that surgery can no longer wait. Her need to settle the house before surgery is why she came so suddenly. When Catherine prepares to leave for preoperative tests and offers to drop Finley at home, Finley surprises herself by choosing to stay. She does not want someone else to decide her next move.
Her relationships at the lake deepen. Anne, Finley's cousin and the bride-to-be, embraces her warmly. Lana, the Egg's waitress, who has been sleeping on the Woods couch, accepts the spare bed in Finley's room. Finley and Ben grow closer through nightly meetings on the Egg's loading dock, where they trade "shame reels," their most embarrassing memories. He smooths a bug off her forehead, their first physical contact, and on a later night they share their first kiss. They call their dual modes "Daytime Us" and "Nighttime Us."
Catherine collapses at the estate sale, forcing her illness into the open. At the hospital, doctors note her anemia and low blood pressure alongside her upcoming cancer surgery. After discharge, she faints again, leading to a second hospitalization. A visiting nurse named Geralin begins daily check-ins. Jeremy, an eco-designer from the Tides, tells Finley that Catherine has spoken of her proudly more than once, catching Finley off guard.
One evening by the water, Catherine reveals why she stayed away for decades. During the summer of her parents' thirtieth anniversary, she saw her father, the Judge, with a waitress from a local bar. When she confronted him, he denied it. Unable to participate in what she saw as a collective lie, Catherine cut ties with her family. She tells Finley that leaving her as a toddler was different: She was unhappy and did not want her sadness to become Finley's. Finley asks if there might be a middle ground between "all and nothing." Catherine agrees: "Somewhere in the middle" (285).
Anne calls off her wedding to her fiancé, Jonathan, after months of having her preferences overridden by Jonathan's mother, Kathy, and a hired planner. The family rallies around her. That evening, the sisters dance together for the first time, and Finley pulls Ben onto the floor. The next day, Jonathan arrives in a panic, and Anne finishes his sentence: "All in" (308). The wedding resumes at the Woods, on their terms. Jeremy discovers that protected plant species on the property may prevent the Tides from razing the land, and he and Catherine work side by side, their connection evident to everyone.
Finley finally activates a new phone and is flooded with messages from Colin, who has quit his job and is driving aimlessly. That night, a notification interrupts her and Ben on the loading dock. He withdraws, then tells her he needs something visible, proof that what is between them is not all in his head. Before she can respond, Colin tracks her phone and arrives at the Woods, inserting himself into wedding preparations. Ben tells Finley flatly that nothing has changed.
On the eve of the wedding, Finley and Colin sit on the dock. He confesses he has been struggling with anxiety since a panic attack during his graduation speech. She admits she had doubts too but recognizes that letting him back in would erase everything she has become. His taillights disappear down the driveway. Later, unaware Finley is listening, Catherine tells her sisters about the Judge's infidelity, the secret she carried for decades. Both already knew. Kasey says that all of it has to be taken together. Finley steps onto the porch, and Catherine's face shifts from surprise to gratitude.
On wedding morning, Finley learns that Ben's band, Sudden Constellation, played a showcase gig the previous night, one he had long refused out of fear. She realizes he pushed past his shame reel without her noticing, consumed as she was by Colin's arrival. At the ceremony, Anne walks down a makeshift aisle as Ben plays "Light of a Clear Blue Morning" by Dolly Parton. Lana slides onto the piano bench beside Cardoon, a regular at the Egg, and takes his hand. Catherine sits next to Jeremy.
After the ceremony, Finley spots Ben heading toward the driveway. She runs after him, calls his name in front of the wedding guests, and kisses him. He lifts her up, and the celebrants cheer. The group gathers on the front steps for a photograph echoing the "porch pictures" Liz once described, but with a new, expanded family. Finley resolves to be fully present for whatever comes next: all, nothing, and everything in between.