For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
Act I goes from Chapter 1 to Chapter 4, and it goes something like this: One day in London Phileas Fogg, confirmed bachelor with OCD, is playing whist in his club with several dudes. He explains that he's read in a newspaper that it's now possible to go around the world in eighty days. No one believes this, and Phileas puts it out there that he could do it. Much scoffing ensues and Phileas lets all his chaps know that he plans to do it. He bets 20,000 pounds just to wipe the smiles off their faces. The dudes with nothing better to do accept, and Phileas leaves that night with his newly hired French servant, Passepartout.
Act II
Act II runs from Chapter 5 to Chapter 34. The plot thickens as Phileas is stated to look remarkably like the "gentleman" who robbed the Bank of England just a few days ago. This "gentleman" took a few thousand pounds and made off with it. Detective Fix is on the case—following Phileas as he journeys around the world, spending what the Detective anxiously thinks is the stolen money, a percentage of which will be his as a reward for bringing in the thief.
Fix and his suspicions get in the way of Fogg's journey as he first befriends Passepartout and then ultimately uses him to thwart Fogg's efforts. In the middle of India, a daring rescue of a princess about to be burned to death occurs, and Phileas's gentlemanly ways become attractive to an ever-so-grateful woman. Fix helps Fogg while in America, but later when they reach English soil again, he's finally able to arrest him.
Act III
Act III goes from Chapter 35 to Chapter 37. It's a sad, sad world now that Phileas Fogg is in jail and won't be able to show up at the club to gloat that he actually did what he set out to do. Passepartout nearly rips all his French hair out at the sheer frustration of it all. But Fix comes on back and tells them all that he was wrong, Fogg isn't the bank robber—um sorry about that. Fogg punches him right in the nose and heads home to mope.
Aouda makes things all better by proposing marriage to Fogg, and they decide to get hitched even though everyone is stupid broke. Passepartout realizes that Fogg miscalculated the days (oh snap) and that they actually made it back to London in time to win the bet. The bet's collected, the marriage is made, and the money is passed out—even to Detective Fix, 'cause you know, Fogg's such a good guy and all and everyone's happy to be rich, or just happy to be happy.