Lewis, portrayed by Daniel Hansen and Jordan Fry, is an inventive young boy who has spent his early years in an orphanage after being left there by his mother as an infant. He eagerly attempts to impress potential adoptive parents with his latest inventions, but when one of his demonstrations goes awry due to a nut allergy, his hopes of being adopted start to dwindle. Approaching his thirteenth birthday, Lewis fears that his chances of finding a loving family are slipping away. Driven by the hope of reuniting with his birth mother, he dedicates himself to creating a memory-scanning machine.
His relentless dedication forces his roommate, Mike Yagoobian (Goob), into sleepless nights, which ultimately leads Goob to miss an important little league game. During the school science fair, Lewis meets a mysterious boy named Wilbur Robinson, who claims to be a "time cop" from the future, needing Lewis's help to retrieve a stolen time machine. This machine is in the clutches of the sinister Bowler Hat Guy, who employs a robotic hat named Doris to sabotage Lewis's inventions. As chaos erupts at the science fair, Lewis's memory scanner malfunctions, leaving him vulnerable to the villain's schemes.
After Wilbur convinces Lewis of his genuine intentions, the two embark on an extraordinary journey to the year 2037 in a flying time machine. As they explore the futuristic world, Lewis becomes increasingly tempted to use the machine to travel back to find his mother. Wilbur insists on first repairing their future predicament, which leads to a series of challenges and misunderstandings. They crash the time machine, and after some negotiation, Lewis agrees to fix it with the condition that Wilbur will help him locate his mother afterward.
While hiding in Wilbur's garage, Lewis meets the eccentric Robinson family, including Wilbur's grandfather, Bud. Despite their warmth and the possibility of adoption, Lewis is torn when he learns of his past. The stakes are raised when Bowler Hat Guy and Doris follow them to the future, attempting to capture Lewis and exploit his memory scanner technology to change the course of history.
Lewis’s journey takes a darker turn as he confronts his old friend Goob, who has transformed into the resentful Bowler Hat Guy, blaming Lewis for his unfortunate life choices stemming from a lost baseball game. This revelation forces Lewis to face the weight of his past and its impact on his future. In a gripping showdown, he discovers the catastrophic consequences of Tampering with time as the future begins to unravel.
With the help of Wilbur and Carl, a robot, Lewis fights back against Bowler Hat Guy’s evil plans. Yet, as they race through time, Lewis realizes the importance of letting go of the past. In a dramatic conclusion, he manages to reconfigure the timeline to save his friends, restore his family connections, and secure a hopeful future for himself.
In a heartwarming resolution, Lewis embraces his identity as Cornelius, the inventor he aspires to be. He leaves the orphanage to begin anew with the Robinson family, surrounded by love and support. The film closes with a powerful message from Walt Disney, reminding us to cherish the future and our curiosity: > "Around here, however, we don't look backwards for very long. We keep moving forward, opening up new doors and doing new things, because we're curious... and curiosity keeps leading us down new paths."
