For generations, the Beaumont family has harbored a magical secret. They each possess a "savvy"--a special supernatural power that strikes when they turn thirteen. Grandpa Bomba moves mountains, her older brothers create hurricanes and spark electricity . . . and now it's the eve of Mibs's big day.

As if waiting weren't hard enough, the family gets scary news two days before Mibs's birthday: Poppa has been in a terrible accident. Mibs develops the singular mission to get to the hospital and prove that her new power can save her dad. So she sneaks onto a salesman's bus . . . only to find the bus heading in the opposite direction. Suddenly Mibs finds herself on an unforgettable odyssey that will force her to make sense of growing up--and of other people, who might also have a few secrets hidden just beneath the skin.