While Christmas shopping at
Bloomingdale's in New York City, Jonathan Trager meets Sara Thomas, a British woman, when both try to buy the same pair of gloves. Despite both being in relationships, a mutual attraction leads them to have dessert at a restaurant called
Serendipity 3 where Sara explains that she lets fate's "little signals" determine many of her life decisions. After separating, they meet again when each returns to the restaurant to retrieve something they forgot. Jonathan convinces Sara to give him her phone number but when the wind blows it out of his grasp, Sara thinks it’s fate telling them to back off. Jonathan disagrees and Sara decides to let fate reunite them: she has Jonathan write his number on a five-dollar bill which she uses to buy breath mints, and promises to sell her copy of
Love in the Time of Cholera, in which she will write her name and number, to a used bookstore. As one last experiment, Sara tosses Jonathan one of the gloves. They board separate elevators in the
Waldorf Astoria and agree that if they arrive on the same floor, they are meant to be together. They each pick the same floor but Jonathan is delayed when a child on his elevator presses random buttons. Sara believes that the experiment failed. A few years later, Jonathan is an
ESPN producer engaged to Halley, and Sara is a therapist living in San Francisco, engaged to a musician, Lars. Jonathan accidentally finds his glove and goes out with his friend Dean to find Sara. Meanwhile, Sara, stressed by the wedding planning and Lars' focus on an upcoming world tour, travels to New York with her best friend Eve to find Jonathan. After nearly crossing paths with Jonathan throughout the day, Sara and Eve have dessert at Serendipity where Eve convinces Sara to give up; unnoticed by them, Eve's change contains the five-dollar bill with Jonathan's number. They catch the same cab Jonathan and Dean rode in earlier. After finding that a roommate finder service next to Serendipity that Sara once used is now a bridal shop, Jonathan sees it as a sign that he should marry Halley. At the Waldorf Astoria, Sara and Eve encounter Halley headed to the wedding rehearsal. Halley invites Eve to join her since they were friends in college, but Sara declines. Outside their room, she finds an apologetic Lars. At the rehearsal, Jonathan's distracted demeanor frustrates Halley, who pleads with him to focus on the wedding. Halley then gives him Sara's old copy of
Love in the Time of Cholera as a wedding gift. Jonathan and Dean use Sara's phone number to obtain her address and fly to San Francisco. Once there, they see Sara's sister and her boyfriend having sex and assume it is Sara in a happy relationship. Dean helps Jonathan realize that he should not marry Halley while Sara decides to end her engagement to Lars. The next day, Sara finds the five-dollar bill with Jonathan's number on it, having gotten hers and Eve's wallets mixed up. After obtaining his address and being told by the building superintendent of his wedding at the Waldorf, Sara hurries there and is relieved to find the ceremony has been canceled. Dean reassures Jonathan that he did the right thing and vows to be more spontaneous in his own marriage, which has been on the rocks. Jonathan wanders to the same ice skating rink where he spent part of his evening with Sara seven years earlier and finds a leather jacket on a bench. As it begins to snow, he lies on his back in the middle of the rink with the jacket as a pillow next to one of the pair of gloves. When the matching glove lands on his chest, he sits up and finds Sara watching him, having come to claim her jacket. They introduce themselves and finally share a kiss. Some time later, they celebrate their anniversary at Bloomingdale's in front of the display of gloves where they met. ==Cast==