Jeronicus Jangle, a talented inventor, toymaker, and proprietor of Jangles and Things, is on the brink of a life-changing moment as he receives the final piece for his latest creation—a component that can breathe life into toys. His first animated creation is Diego, the charming matador. As Jeronicus and his family celebrate Christmas, he entrusts Diego and the store's operations to his apprentice, Gustafson. However, Diego, distressed by the thought of being mass-produced and losing his individuality, persuades Gustafson to conspire against Jeronicus, leading to the theft of Diego and Jeronicus's book of inventions. Without any evidence to present to the authorities, Jangles and Things succumbs to financial despair, while Gustafson ventures off to start his own toy factory.
As time passes, Jeronicus grapples with the heartache of losing his wife, Joanne, and grows estranged from his daughter, Jessica, who ultimately leaves home. Thirty years later, Jangles and Things has devolved into a struggling pawnbroker shop, and Jeronicus has lost his creative spark. His fortunes seem bleak until he meets Ms. Johnston, a compassionate postwoman who takes an interest in him and seeks to uplift his spirits.
Things worsen when Mr. Delacroix, played by Hugh Bonneville, presses Jeronicus to either clear his debts or present a new invention by Christmas, or risk losing his beloved shop. Meanwhile, we are introduced to Jessica's daughter, Journey, who inherits her grandfather's inventive spirit. A letter from Jeronicus is received by Jessica, prompting her to send Journey to spend time with him until the holiday.
Arriving at her grandfather's shop, Journey is met with indifference, yet he reluctantly agrees to host her. The once-promising Gustafson, now a successful tycoon, has completely depleted Jeronicus's inventive ideas. During a gala, Gustafson extravagantly reveals his new toy design, the Twirly Whirly, but it quickly malfunctions, creating chaos among the attendees. Inspired by Diego, Gustafson is compelled to steal another of Jeronicus's inventions.
In the dimly lit workshop, Jeronicus is tirelessly focused on his next groundbreaking toy, The Buddy 3000, a creation rooted in Jessica's vision. Journey becomes determined to see it come to life. One fateful night, as she sneaks into Jeronicus's workshop, she encounters his assistant, Edison. Together, they unearth Buddy's dormant form and, with a quick hand, activate the mechanism Jeronicus was working on. But when Jeronicus walks in, Buddy suddenly powers down. Alone, Jeronicus reflects on the distance that has grown between him and his daughter, as well as the profound grief over his wife.
Meanwhile, Journey and Edison soon discover that Buddy has fallen into the hands of Gustafson. They ingeniously infiltrate his factory just in time to thwart a failed demonstration of Buddy. As Gustafson orders Buddy's destruction, Journey and Edison cleverly retrieve him. Realizing their absence, Jeronicus takes action, storming into Gustafson's factory. With the assistance of Jeronicus and Buddy, the duo escapes the factory but not without damage to Buddy. Ms. Johnston arrives just in time to help them elude Gustafson and his thugs.
Upon returning, Journey confesses to Jeronicus that she wrote to Jessica in hopes of reconnecting with him. Inspired to mend relations with Journey and Jessica, who arrives searching for her daughter, Jeronicus resolves to repair Buddy. A confrontation ensues when Jessica holds Jeronicus accountable for his years of neglect, prompting him to reveal unsent letters he had kept hidden, voicing his regrets. Together, they work through the night to restore Buddy.
The climax unfolds when Jeronicus's family faces accusations from Gustafson, Diego, and the police regarding Buddy's alleged theft. Yet, Journey boldly disproves these claims. In a pivotal moment, Jeronicus reprograms the component of Diego, bringing a sense of redemption. As Gustafson is apprehended, Jeronicus offers him a piece for his Twirly he had intended to give—had Gustafson been patient.
In the end, Mr. Delacroix visits the shop and, struck by Buddy, enthusiastically promises Jeronicus the funding needed for any of his inventive ambitions. The narrative is portrayed as an older Journey sharing the tale with her grandchildren, showcasing a working Buddy. She takes them to the revitalized Jangle factory, previously owned by Gustafson. As the credits roll, a delightful montage encapsulates the resurrection of Jangles and Things, the success of Gustafson's Twirly Whirly, the mass production of Diego's toy, and the grand opening of Jeronicus's factory.
