Rosie mistakes Lina's cousin Lucas for a burglar when he arrives at Lina's apartment with a key.

Lucas proposes a five-question game at the diner, through which Rosie admits she quit engineering to write romance novels.

Rosie and Lucas agree to share Lina's apartment without telling Lina, who is still on her honeymoon.

Rosie breaks down crying over her unfinished manuscript outside her flood-damaged apartment, and Lucas comforts her.

Lucas proposes a dating experiment with four staged dates to inspire Rosie's writing, promising not to fall in love with her.

On their first experimental date at a record store, Rosie selects ABBA's 'Dancing Queen' as their official soundtrack.

A rat emerges from the record player box and interrupts Rosie and Lucas's dance on their first date.

On their second date making pizza, the food burns as Rosie and Lucas nearly kiss for the first time.

Lina returns from her honeymoon and discovers that Rosie and Lucas have been secretly living together.

At the Halloween masquerade ball, a stranger soaks Rosie's dress, leading to a charged encounter with Lucas in the bathroom.

For their fourth date, Lucas recreates a wedding scenario on a restaurant rooftop with string lights, a cake, and wedding photos.

Club owner Jimmy kicks Lucas in his injured leg during the rescue of Olly from the nightclub.

Lucas comes to Rosie's repaired apartment late at night and the two have sex for the first time.

Rosie chases Lucas to the airport to confess her love and longtime crush, but he refuses her offer to join him in Spain.

Lucas surprises Rosie at a New Year's Eve party at midnight, declaring his love and plans to pursue culinary school in New York.

When Rosie's apartment floods and she is staying at her best friend Lina's place, Lina's cousin Lucas arrives unexpectedly and the two end up sharing the apartment in secret. Struggling with writer's block on her romance novel, Rosie agrees to Lucas's proposal of four staged experimental dates designed to inspire her manuscript without romantic strings attached. Their dates are full of mishaps and growing chemistry, complicated further when Lina returns from her honeymoon and Rosie's brother Olly lands in serious danger at his nightclub job. After rescuing Olly, Rosie and Lucas finally admit their feelings and become a couple, but Lucas's deep sense of unworthiness leads him to reject Rosie's dramatic airport declaration of love. Lina eventually pushes Lucas to confront his self-doubt by sharing Rosie's finished novel as proof of his impact on her life. He shows up at a New Year's Eve party to make his own grand gesture, and the two commit to building a real future together.

The central romance from awkward first meeting to happy reunion.

Lucas falls through Lina's apartment doorway when Rosie opens the door, partly because of his hidden leg injury.

Rosie visits her father in Philadelphia but cannot reveal her career change because he is already visibly worried about Olly.

Lucas cooks an impressive dinner on Rosie's first evening back at the apartment, and the two bond while watching a vampire drama together.

Rosie and Lucas help their elderly neighbor Adele try to move furniture and realize she is living with dementia.

Lucas accompanies Rosie to her flood-damaged apartment to face her difficult landlord alongside her.

Rosie's landlord threatens to evict her over the water damage, and Lucas intervenes before they nearly come to blows.

Adele's daughter Alexia arrives at the apartment to thank Lucas for his care of her mother and reveals she is a famous chef.

During a return visit to her father in Philadelphia, Rosie meets his neighbor Nora, who is clearly romantically interested in him.

On their second date, Lucas confesses that his leg injury did not pause but permanently ended his professional surfing career.

Alexia suggests Lucas attend culinary school after observing his passion and skill in the kitchen during a dinner at the apartment.

Rosie surprises Lucas by revealing she secretly arranged for his sister Charo and his dog Taco to come to New York to support him.

Lucas takes Rosie to Alexia's restaurant Zarato for their fourth-date dinner and whispers Spanish to her over the menu.

Olly explains he started working at the strip club to impress a girl and got into trouble when he tried to protect her from the owners.

Rosie finally tells her father and Olly the truth about her career change as a romance writer, and her father voices full support.

In the Epilogue, Lucas arrives at Rosie's apartment a full day earlier than she expects, surprising her from the hallway.

While the central romance between Rosie and Lucas unfolds, a series of secondary events quietly define who they are and deepen the bonds around them. Lucas's first stumble through the apartment door hints at the hidden injury he is not yet ready to discuss, and Rosie's failed trip to confess her career change to her father sets up her pattern of keeping secrets to avoid disappointing the people she loves. Their elderly neighbor Adele and her famous-chef daughter Alexia become unexpected catalysts, drawing out Lucas's compassion and planting the seed of a culinary career. Rosie's discovery that Olly was hiding a dangerous job mirrors her own habit of concealment, while her father's quiet romance with neighbor Nora offers a gentler reflection of love blossoming in unlikely circumstances. By the end of the novel, Rosie has finally told her family the truth about her life, Olly has explained his own secrets, and Lucas fulfills the promise Alexia first saw in him by committing to culinary school. The Epilogue closes the loop by returning Lucas to Rosie's doorstep — this time for good.

The supporting moments that shaped Rosie and Lucas's world.

Lucas offers to leave Lina's apartment and find a hotel so Rosie can stay, promising to return the next day.

Rosie finds Lucas sleeping in a diner and learns he could not afford a hotel because his credit card is missing.

During a video call with his sister Charo, Lucas introduces Rosie to his family while carefully hiding that his surfing career has ended.

Lucas reveals that his grandfather struggled with Alzheimer's disease, explaining the empathy and patience he shows toward neighbor Adele.

Lucas brings Rosie Cronuts during her existential crisis, and the two invent 'cronut you' as their private shorthand for gratitude.

Olly arrives at Lina's apartment with visible signs of a fight and tells Rosie his nightclub job involves threatening and dangerous men.

Lucas arrives in a matching Victorian costume to escort Rosie to the Halloween ball and presents her with a corsage she never received at prom.

In the bathroom at the Halloween ball, Rosie asks Lucas to look at her in her underwear and he openly admits his attraction to her.

Lucas appears at the coffee shop and declares he and Rosie already have plans for the evening, just as contractor Aiden Castillo asks Rosie on a date.

In bed after rescuing Olly, Lucas finally tells Rosie that a surfing accident in France caused his leg injury and ongoing panic attacks.

Rosie tells Lucas that his accident changed him but did not diminish him, refusing to let him describe himself as broken or unworthy.

Rosie moves back to her repaired apartment and Lina confronts both her and Lucas, warning them she can sense their obvious chemistry.

Rosie finishes her romance manuscript and tells Lucas the book would not exist without his presence in her life.

Rosie reveals the dating experiment to Lina, who apologizes for her skepticism and admits Aaron secretly helped Lucas plan the rooftop date.

Lina tricks Lucas into answering her call and tells him that Rosie's finished novel is proof of his worth to her.

Beneath the surface of Rosie and Lucas's budding romance lies a series of quiet but decisive moments in which hidden truths come to light and small choices ripple outward. Lucas's early act of selflessness — offering to leave the apartment so Rosie can stay — sets the tone for his protective instincts, while the revelation of his missing credit card adds a layer of vulnerability he usually hides behind charm. As their experiment unfolds, each date peels back another layer: a corsage that repairs an old prom wound, an underwear-clad admission in a bathroom that neither can take back, and a bedtime confession about a surfing accident in France that finally names the grief Lucas has been carrying. Rosie, in turn, meets each revelation by refusing to let Lucas diminish himself, and by finishing a novel that quietly immortalizes him. When Lina tricks Lucas into a phone call and tells him Rosie's book is proof of his worth, the last barrier to his return crumbles. These are the turning points that made the happy ending possible.