Peabody (voiced by Ty Burrell) is a unique puppy with an incomparable high IQ, so it is destined to have a "dog life" that is very different from its peers. It holds a Harvard degree, has successfully developed new energy, satisfactorily solved geopolitics, and founded its own company. Peabody adopted Sherman (voiced by Max Charles), a human orphan who had a similar experience to it, by chance. It educated his son like a kind father, and used the time machine it developed to take Sherman back to every important moment in the future to experience the boring historical events in the books. In a blink of an eye, Sherman reached school age. His rich historical knowledge was praised by the teacher, but it also attracted the jealousy and bullying of the arrogant little girl Penny Peterson (voiced by Ariel Winter). The conflict between Sherman and Penny put Peabody into an unprecedented difficult situation. In order to keep the custody of Sherman, it tried its best to please Penny's parents and the heads of relevant institutions. And that night, Sherman and Penny secretly boarded a time machine and embarked on a thrilling adventure in time and space...