At first glance, it's a female version of Big. A 13-year-old wishes to be grownup and becomes a grownup. Tom Hanks' childlike spirit saves a toy company. Jennifer Garner's childlike spirit dreams up a winning new look for a failing magazine.

There the similarity ends except for an occasional show-stopping scene. (Garner's revival of Thriller is reminiscent of the scene in Big where Hanks plays piano with his feet at F.A.O. Schwarz). Garner's character, Jenna, doesn't just become a 13-year-old in a 30-year-old body. She pops into her own future, a future in which she has whatever she wanted at 13. She went to the prom with the cute boy, became one of the popular girls and now works as an editor at the fashion magazine she loved at a younger age. She doesn't remember anything in between.

Predictably, she finds that being a grownup, even a successful grownup, is not all it's cracked up to be. She also comes to the painful realization that what's bad about her life is her. What's worse is that it's not fixable.

What makes the movie work, and it works wonderfully, is the emotion. Garner brings us into her world and shares with us the sting of lost dreams and mistakes that can't be undone. On one level, the movie works as a comedy of a child in an adult's body. On another level, it paints the picture of an adult realizing she has betrayed her own childhood vision.