Jenna makes a wish on her 13th birthday to be 30 and grown up. When she wakes up the next day she finds herself, miraculously, just weeks away from her 30th birthday. The new, older Jenna is a successful magazine editor with friends in high places and a lion's share of potential suitors. The problem is that her mind hasn't matured with her body and Jenna finds it a little more terrifying than cool to be living on her own.

Although he has been missing for several years and the entire town thinks her father has abandoned her family, Meg steadfastly believes the best and protects her younger brother, Charles Wallace, from the brunt of the rumors and taunting. It is he, however, who convinces her to join him, the school sports star Calvin, and three unusual women on an interplanetary voyage to rescue their father from a vast evil.