The excellent adventure continues as Alex Winter and Keanu Reeves return for Bill & Ted Face the Music -- and the stakes have never been higher.

As revealed in the first teaser trailer, Bill (Winter) and Ted (Reeves) are still best friends all these years later and still set on uniting mankind. This time, they'll have a little help from their daughters (Samara Weaving and Brigette Lundy-Paine) on their time travel adventures, as the duo seek a song that will bring about world peace.

"Bill, we've spent our whole life trying to write the song that will unite the world," Reeves' Ted says in the preview. "Why can't we just go to the future when we have written it?"

"And take it from ourselves!" Bill replies.

"But isn't that stealing?" Ted ponders.

"How is that stealing if we're stealing it from ourselves, dude?" Bill reasons.

The Bill & Ted threequel hails from screenwriters Chris Matheson and Ed Solomon, who were also behind Excellent Adventure and Bogus Journey, with Dean Parisot (Galaxy Quest) stepping in to direct. Kid Cudi, Kristen Schaal, Jillian Bell and Holland Taylor also star.

Bill & Ted Face the Music is in theaters Aug. 21.

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