A trouble making boy named Phineas and his friend Irving sneak into the local gentalmen's club and unwittingly bet against arrogant billionare Heinz Doofenshmirtz that they can travel around the world in 80 days, with the prize of $1,000,000. After "borrowing" a hot air baloon, they begin their journey. Along the way they rescue a beautiful princess named Isabella from an unwillful marriage. Meanwhile Doofenshmirtz follows the kids to delay them, so he can win the bet.
Phineas- An impulsive 10 year old boy, who takes any oppurtunity for action. Although he seems reckless he will risk his life for his friends.
Irving- Phineas' sidekick, he is energentic and lovable, but clumsy. He sometimes questions Phineas' reckless action but is easily convinced otherwise.
Isabella- An Indian princess is just as compassionate and adventurous as Phineas. She and Phineas secretly have a crush on eachother.
Heinz Doofenshmirtz- A greedy and short-tempered billionare, who has a knack for gambling, and isn't afraid to cheat. He is physically weak and somewhat cowardly, so he hires mercenaries to do his dirty work.
Ferb- member of the Tri-State Area gentalmen's club and the one person who believes Phineas can win Doofenshmirtz's bet