17 Again (2009) 17 Again is a comedy film starring Zac Efron and Matthew Perry. The story follows Mike O’Donnell, a man who feels disappointed with how his life turned out—his marriage is falling apart, and his career never took off. One day, after a strange encounter with a mysterious janitor, Mike magically transforms back into his 17-year-old self. Now attending high school again as “Mark,” he gets a second chance to fix his past mistakes, reconnect with his kids, and rediscover what truly ma