Bill & Ted Face the Music
In the movie, Thea and Billie see Kelly meet with their dads to give them a warning that if they don’t create a song to unite humanity across all time, two time periods will glitch into one another.
Billie and Thea want to help their fathers create the song. Using Kelly's time machine, they enlist the help of historical figures all throughout music history, such as Jimi Hendrix, Louis Armstrong, Wolfgang Amadeus Mozart, Ling Lun, and a cavewoman named Grom, to form a band that would play alongside their fathers.
Billie, Thea, and the rest of the group return to present day San Dimas where they realize, along with their dads, that the prophecy about who will save the world is not actually Bill and Ted but rather Billie and Thea. The girls take action and attempt to connect every part of the song as coherently as possible.
Thea and Billie's song is powerful enough to restore the balance of time and space, finally uniting the world and all across time.
- Bill and Ted: Face the Music (film)