17 Again is a 2009 American comedy film directed by Burr Steers. It is the story of 35-year-old Mike (Matthew Perry) who becomes a 17-year-old high school student (Zac Efron) after a chance accident. The film was released in the United States on April 17, 2009. It was set in 2007 (it was originally supposed to be released in 2008, but was delayed until the following year), as evidenced by the date on the cell phones of several students (during a scene where Efron is beaten up by the school bully), and also by the age of Mike and Scarlett's eldest child, Maggie (she's a 17 or 18 year old high school senior)

In 1989, 17 year-old Mike O'Donnell learns from his girlfriend Scarlett that she is pregnant during the start of his high school championship basketball game. Moments after the game begins, he abandons the game and goes after Scarlett.

Nearly 18 years later, Mike finds his life stalled. Scarlett has separated from him due to his regrets about abandoning college, forcing him to move in with his geeky and wealthy best friend since high school, Ned Gold. At his job we see another reason for his frustration as he is significantly older than most of his co workers and he passed over a promotion he deserves in favor of a much younger female worker, he gets fired from his job (after smashing his boss's bluetooth against the wall) and his high school-age children Maggie and Alex (Maggie is 17 or 18 but we never discover how old Alex actually is) want nothing to do with him. Later, while visiting his high school to reminisce, an encounter with a mysterious janitor transforms Mike into his 17 year-old self.