Vicky, portrayed by Rebecca Hall, and Cristina, played by Scarlett Johansson, embark on a summer adventure in Barcelona, where they stay with Vicky's relatives, Judy and Mark. A Narrator, voiced by Christopher Evan Welch, provides insights into the contrasting personalities of the two friends; Vicky is practical and engaged to the reliable Doug (Chris Messina), while Cristina is spontaneous, recently out of a tumultuous relationship, and in search of her identity.
At an art exhibition, they encounter the captivating artist Juan Antonio, brought to life by Javier Bardem. Cristina is immediately intrigued by him, especially after hearing about his dramatic past with his ex-wife, María Elena. That night, while dining, Juan Antonio draws closer, charmingly asking Cristina about her eye color before unexpectedly inviting both women to join him in Oviedo for a weekend of adventure, wine, and romance. Though initially hesitant, Vicky succumbs to the idea, leading them to travel during a storm aboard Juan's friend's private plane.
In Oviedo, after sightseeing and indulging in good wine, the tension escalates. While Vicky chooses to resist Juan's advances, Cristina, unfortunately, falls ill just as their plans heat up. During this unexpected turn, Vicky and Juan forge a connection as they sightsee together. Through genuine conversations about love and heartache, the two share a romantic encounter, forever changing their dynamics.
Upon returning to Barcelona, Vicky struggles with her guilt about the fling and distances herself from Cristina, who starts a romance with Juan. Meanwhile, Doug proposes a spontaneous wedding in Spain, which Vicky, with mixed emotions, agrees to while throwing herself into her academic research. Cristina and Juan's relationship grows, and María Elena, after a crisis, moves in, forming a complicated love triangle that intertwines their lives even further.
As Vicky navigates her feelings for Juan and observes Judy's infidelity, she unearths her dissatisfaction with her own future. Judy, convinced of the connection between Vicky and Juan, orchestrates a series of events hoping to rekindle their romance. However, Cristina realizes she can't endure a long-term polyamorous relationship and decides to leave for France, inadvertently leading Juan and María Elena to confront their own toxic cycle.
A chaotic party leads to a pivotal moment, where Vicky is thrust into danger as María Elena's emotions spiral out of control. The climax sees Vicky shot accidentally, forcing her to confront the disarray in her heart and life. When Cristina returns, Vicky divulges her tumultuous summer, while Doug remains blissfully unaware of the deeper truths. As they return to the US, Vicky opts for her predictable life, while Cristina is left in a state of uncertainty, ultimately both friends navigating their paths back to where they began, but forever altered by their experiences.
