'Chasing Mavericks' Trailer: Gerard Butler Surfs Legendary Waves (Video)

The movie, based on the true story of surfing icon Jay Moriarty, hits theaters Oct. 26.

Gerard Butler faces some serious surf in Chasing Mavericks, an upcoming movie based on the true story of surfing legend Jay Moriarty.

In the movie, from 20th Century Fox and Walden Media, Butler plays Northern California surfing legend Frosty Hesson, who is enlisted by a 15-year-old Jay (newcomer Jonny Weston) to help him train to surf the mythic Mavericks surf break -- one of the biggest waves on Earth -- once he discovers that it's real.

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The new trailer shows that Frosty is initially reluctant, telling Jay: "That wave is a myth, and the four of us who surf it intend to keep it that way."

He also warns Jay: "One wrong turn, you're hitting the water like concrete at 50 miles an hour."

Realizing Jay intends to surf the Mavericks with or without his help, Frosty gives in -- but they have only 12 weeks to train, as the window for the swells that cause the huge waves closes then.

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The film, which co-stars Elisabeth Shue, Abigail Spencer, Taylor Handley, Scott Eastwood and Leven Rambin, hits theaters Oct. 26.