Not everyone is out to "save the cheerleader."

Hayden as Claire Bennett on Heroes Credit: NBC

Playing pom-pom princess Claire Bennet on NBC's Heroes, actress Hayden Panettiere must stay in fighting form to save the world. That's why Hollywood's newest "it" girl can often be found pumping iron at the celeb-friendly gym Crunch, with its brightly colored walls and hall of showers with translucent doors.

After working up a sweat, Panettiere takes a breather at a coffee shop. "Crazy" is the word she uses to describe Monday night's (April 30th)episode, which flashes five years into a possible future with the heroes having failed in their season-long mission to save New York from devastation.

As the season reaches its climax May 21, Panettiere teases, "Claire has to make a very hard decision. She is put in a position of serious power -- to stop (destruction) in a pretty heartbreaking way. Or not."

Hayden Panettiere Credit: NBC

Less than six years ago, Panettiere lived through a nightmare scenario similar to tonight's "what if" episode. Up until this year, her family lived in New York, and her father, Skip, retired as a fire department lieutenant just six months before the 9/11 attacks.

The family mourned many lost friends.

Panettiere was left with an enriched appreciation for life. "I want to go crazy," the 17-year-old says of her own future.

Uh-oh.