Mr. Hector Peabody, the smartest being existence who is also a beagle, tells the audience the story of his life, including his early experiences, and his adoption of Sherman, his very own pet boy. He also tells the story of how he built the WABAC time machine.
Mr. Peabody and Sherman travel to 1810 where they meet Napoleon who is missing his royal suspenders. So, Peabody and Sherman must get them back from some pirates. But when they get them back, they're shocked to see everyone is glad with Napoleon occupied.
Lord Nelson is unable to go into battle against the Spanish fleet as his crew has left port minus one important commodity. Now it's up to Peabody to help him get into battle.
Dodge City's famed sheriff is unable to face "Aces Wilde" in a gun showdown, due to some bad luck and a leg injury, sending Peabody to do "a man's job."
Everything is out of hand in King Arthur's kingdom, a dragon is terroizing the kingdom and all the knights are too weak and pathetic to fight the dragon and Mr. Peabody decides to use a new strategy. He uses Sherman's bubble gum.
Peabody and Sherman go back to the year 1824 and meet Franz Schubert. They decide to help him compose his latest musical masterpiece. But his piano is stolen by his next door neighbor and he wont give it back.
Lucretia Borgia, the worlds best poison artist has just gotten a 12th husband who is snacking on furniture. Peabody and Sherman try to get the husband to leave Lucretia but he loves her too much to bail out on her. So, Peabody creates a special potion for him that will make the man impervious to poison so he will live and not leave his wife.
Sir Walter has a "Dead" line with the Queen to raise his waterlogged cargo or it will be off with his head! Now it's up to Peabody and Sherman to help him.
Peabody visits with Fulton, the famed inventor of the steamboat and helps prove steamboats can outrun the fastest sailboats. But when the workers quit, Peabody must find a way to win the race without new workers. So he paints the boiler room to look like the North Pole.
Forest Primeval attempts to cheat Annie Oakley at a shooting match, until a certain genius dog and his boy intervene.
