Mr. Peabody, an eccentric canine genius who happens to be the world's smartest being, adopts a human boy named Sherman, raising him with the help of his loyal assistant, Penny, and a host of historical figures. Peabody’s motivation is rooted in providing Sherman with an extraordinary education through time travel via the WABAC machine. However, tensions arise when Sherman starts attending school, where he clashes with the pompous classmate Penny Peterson. During a disastrous dinner party meant to mend relations, Sherman breaks the rules of time travel to impress Penny by showing her ancient Egypt, sparking a chaotic chain of events.In Egypt, Penny is accidentally betrothed to King Tutankhamun, and rescuing her requires quick thinking from both Peabody and Sherman. As they navigate through historical eras—including the Trojan War, the French Revolution, and Renaissance Florence—their relationship undergoes significant strain. Sherman begins to pull away from his father's suffocating intellectual shadow, desperate to forge his own identity. Meanwhile, a strict social worker named Miss Grunion becomes heavily involved, threatening to permanently revoke Peabody’s custody of Sherman under the absurd premise that a dog is unfit to raise a human child.The climax reaches a fever pitch when the timeline collapses, causing historical figures and landmarks to violently crash into modern-day New York City. Cleopatra, Leonardo da Vinci, Agamemnon, and
George Washington suddenly roam the streets, creating widespread panic and drawing the intense scrutiny of law enforcement. Peabody and Sherman must put aside their domestic disputes and work together to repair the fractured space-time continuum. Using their combined ingenuity, they pilot the WABAC machine directly into the stratosphere, manually reversing the temporal vortex.During this perilous mission, Peabody’s deep love and
emotional vulnerability toward Sherman are fully revealed, bridging the emotional gap between them. They successfully restore history to its proper place, but the temporal disturbance leaves Peabody stranded in the past momentarily. Sherman bravely steps up to rescue his canine father, proving his growth and independence. In the aftermath, Grunion’s attempt to seize custody is thwarted not just by the grateful historical figures who vouch for Peabody, but also by Sherman himself, who boldly declares that he is proud to be a dog's son. The film concludes with Sherman returning to school, fully accepted by his peers, as Peabody looks on with immense paternal pride, having successfully balanced his scientific brilliance with the messy, beautiful reality of fatherhood.