Preston Esq. (Alex Winter) and Ted "Theodore" Logan (Keanu Reeves) play two high school friends, and Wyld Stallyns band members from San Dimas, CA who make for an unlikely cast to save the world. In their time travels they get the help of many historical figures including Napoleon Bonaparte, Socrates, Billy the Kid, Sigmund Freud, Beethoven, Genghis Khan, Joan of Arc, and Abraham Lincoln.
Like all movies about time travel, Bill and Ted's Excellent adventure raises many questions about the possibility and paradox of time travel. The entire film is an example of the predestination paradox in which Bill and Ted are "pre-destined" to travel back in time in the future forming a self-consistent causal loop.
Spoiler alert: In the final moments of the film, the time travelers exploit the Novikov self-consistency principle in order to break themselves into jail they promise that the future version of themselves to travel back in time and steal their Dad's keys and place them in a predetermined location. In a subtle moment at the beginning of the film, you'll notice that the Dad is missing his keys. Thus, Bill and Ted were pre-destined to succeed. Dude!
