In Bill & Ted Face the Music, we see the return of Keanu Reeves and Alex Winter as the titular characters, who have now grown up to be middle-aged men with families of their own. Despite their earlier time-traveling adventures and their promise to save the universe with their music, they have failed to fulfill that destiny and are struggling to come up with a hit song that will finally make them successful.
The story begins when a visitor from the future, Kelly, arrives with a message that Bill and Ted must write the song that will bring harmony to the universe within the next 75 minutes, or else time and space will collapse. This sets Bill and Ted on a wild adventure through time and space, as they try to gather the greatest musicians in history to form a supergroup that can create the perfect song.
Their travels take them to the future, where they meet their now-adult daughters, Billie and Thea, who have inherited their fathers' love for music and time travel. The quartet sets off on their journey, encountering famous historical figures such as Mozart, Louis Armstrong, and Jimi Hendrix, as well as characters from their own past adventures.
Along the way, Bill and Ted not only search for the song that will save the universe, but also grapple with the idea that they may have been mistaken in their belief that they are the ones who are meant to fulfill this task. The film ultimately serves as a tribute to the enduring friendship between Bill and Ted, as well as the power of music to unite people across time, space, and even dimensions.