Tim Lake, portrayed by Domhnall Gleeson, begins his story by sharing details about his upbringing. Describing himself as always being "too tall, too thin, and too orange," he introduces us to his family: a somewhat aloof mother, [Lindsay Duncan], a laid-back father named James played by Bill Nighy, a quirky uncle who seems to suffer from memory loss, and a free-spirited sister called Kit Kat, played by [Lydia Wilson]. The Lake family has experienced many joyful moments together, particularly during their time at the beach and home in picturesque Cornwall, England.
During a New Year's Eve party hosted by his parents, Tim finds himself in an awkward situation, where he unintentionally spills drinks all over his guests while trying to impress a beautiful blonde woman. As the countdown to midnight ticks down, he clumsily chooses to shake her hand instead of kissing her, leaving her visibly disappointed while others embrace their partners.
The next day, Tim’s father reveals a family secret that leaves him astounded: the men in the Lake family possess the extraordinary ability to travel through time. Although skeptical, Tim learns that to time travel, he must find a darkened space, close his eyes, and concentrate on a specific moment in his life. However, bound by the limitations of this gift, he cannot alter significant historical events.
Eager to test his new-found power, Tim retreats into his wardrobe and successfully returns to the New Year's party, where he avoids previous mishaps and kisses the blonde woman, now thrilled at the chance. When he shares this revelation with his father, he expresses his desire to use this ability to find a girlfriend.
As summer arrives, Kit Kat introduces her friend Charlotte, played by [Margot Robbie], who quickly catches Tim's eye. In a series of humorous and embarrassing encounters while trying to be smooth, he attempts to put sunscreen on her, leading to awkward moments that require time travel to redo. Though they share a genuine connection, Tim ultimately realizes he cannot change Charlotte's feelings for him, leading to a heart-wrenching goodbye.
Transitioning to a new life in London as a budding lawyer, Tim lives with Harry Chapman, a grumpy playwright, and befriends Rory, a supportive colleague. One fateful night, he meets Mary, portrayed by Rachel McAdams, during a blind date at a restaurant. They bond instantly, but a series of misadventures lead Tim into a frantic search for her after a phone number mix-up.
Through various time-traveling escapades, Tim painstakingly navigates the ups and downs of his budding relationship with Mary, including comical instances of thwarted intimate moments, misunderstandings, and the relentless pursuit of love. Along the way, Tim learns valuable lessons about cherishing time and embracing life's imperfections, particularly during moments with Mary’s conservative parents.
Their relationship deepens, culminating in a lively wedding despite the rain, where whimsical time-manipulations lead to mixed-up best man duties, revealing the chaotic yet joyful nature of life. Soon after, they welcome their daughter, Posy, into their lives. Despite their happiness, tragedy strikes when Kit Kat suffers a drunk-driving accident, prompting Tim to use time travel to guide her decisions, which ultimately leads to her healing.
As love and family flourish, Tim grapples with the heart-wrenching realities of losing a parent. With the guidance of his father, he learns to savor every moment—living both the stressful and joyful days fully. They share special moments and bittersweet farewells, illustrating the importance of family bonds.
Eventually, Tim decides to embrace life without the aid of time travel, cherishing the ordinary moments spent with Mary and their growing family. The film concludes with an emotional montage celebrating the beauty of living day to day, highlighting Tim’s growth into a man who appreciates life in all its unpredictable glory. The journey comes to a heartfelt close, leaving a lasting impression on the significance of love, family, and the fleeting nature of time.
