A reconstituted Mr. Bungle assembles in the Eureka public library to perform their unique brand of music.

Yet to fulfil their rock and roll destiny, now middle-aged best friends Bill and Ted set out on a new adventure when a visitor from the future warns them that only their song can save life as we know it. Along the way, they are helped by their daughters, a new batch of historical figures and a few music legends — to seek the song that will set their world right and bring harmony to the universe.