On December 20 at JFK Airport, the Hadley Sullivan is introduced by the Narrator. She’s an American student who is often late and juggling a phone that’s barely charged, and she narrowly misses her flight to London, getting rebooked for the next available seat.
At a nearby charging station, Oliver Jones, a 22-year-old Yale student, lends her his charger. The two strike up a conversation and decide to grab dinner together in the airport food court. Hadley explains she’s headed to London for her father Andrew Sullivan’s second wedding, and she isn’t sure she agrees with the idea of remarriage so soon after her mother’s divorce. Oliver reveals he studies statistical inference and mentions an ongoing research project, leaving Hadley with the impression that he must be headed to a wedding as well because he’s carrying a garment bag.
Once on board, the pair drift apart briefly, but fate intervenes when Oliver discovers his seat belt is broken and he ends up sitting next to Hadley for the flight. As the plane travels, the pair’s connection deepens into something like a budding romance, folded into easy conversations and shared smiles.
When the plane lands, Oliver saves his number into Hadley’s phone, but the device dies and she loses the contact details. With no way to reach him, Hadley proceeds to the London wedding, arriving moments before it begins. She’s torn by her father’s decision to remarry, yet she’s touched by the kindness and consideration of Charlotte, Andrew’s fiancée.
After the ceremony, Hadley overhears guests saying they’ll leave early for a memorial service. She realizes Oliver has come to London not for a wedding but to attend his mother’s memorial. With four hours to spare before the reception, she makes a spontaneous decision to attend the memorial herself.
Meanwhile, Luther Jones collects Oliver at the airport to head toward a Shakespeare-themed memorial, where he reunites with his father Val and his still-living mother Tessa Jones, who is battling terminal lung cancer and wants to attend her own memorial while she’s still able. Oliver admits he’s unhappy that his mother won’t pursue treatment, but Tessa explains that even with treatment she would still die, so she would rather face it on her own terms and stay true to herself.
Hadley eventually finds the memorial and meets Oliver’s family. After an initial confusion about Tessa still being alive, she comes to understand the family dynamics and eventually finds Oliver. He’s glad to see her but tries to minimize his feelings about his mother’s death looming ahead; when she pushes him to be honest rather than rely on statistics, he lashes out and she leaves.
Oliver then delivers Tessa’s eulogy. In it, he confesses that he has tried to measure his life in numbers to bring it into focus, yet he cannot reduce his mother’s presence and meaning to mere statistics.
Back at the ceremony, Hadley discovers she forgot her backpack and attempts to walk back to the wedding reception, only to get lost. She borrows a phone and calls her dad, who comes to pick her up with Charlotte.
Andrew congratulates Hadley for taking a chance and seeking out Oliver, and he and Charlotte apologize for the excitement around including her in the wedding, which unintentionally put pressure on her. Father and daughter reconcile, and they head to the reception together.
After the memorial, Oliver’s family teases him about Hadley, but he argues that chasing a connection isn’t futile, even against long odds. They find Hadley’s backpack, with Andrew’s wedding invitation tucked inside, and they urge Oliver to go after her. Val shares that even if he had known his wife would die from cancer, he wouldn’t have changed a thing, and the family sets out to find Hadley.
Oliver tracks Hadley down at the reception and shares his three greatest fears—germs, the dark, and surprises—rooted in his mother’s illness. He reveals the heart of his research: the statistical probability of love at first sight.
The tale closes with the [Narrator] reminding us of a hopeful future: Hadley and Oliver will stay together for the rest of their lives, be married for 58 years, and have a daughter.
