Ruby Miller and her fiancé, Tom Truby, have questions 1 to 14 almost covered. It's question 15 that has the Maine schoolteacher stumped: Is their relationship strong enough to withstand challenges?

Challenges like…Ruby's twin sister, Stella. The professional muse, flirt and face reader thinks Ruby is playing it safe. And that the future Mrs. Ruby Truby will die of boredom before her first anniversary or her thirtieth birthday, whichever comes first.

Challenges like…sexy maverick teacher Nick McDermott, Ruby's secret longtime crush, who confesses his feelings for her at her own engagement party.

But before Ruby can plan the wedding that may never be, Stella announces she's pregnant by a one-night stand whose name might be Jake (or James? Maybe Jason?) and who lives somewhere under the glittering lights of Las Vegas. Ruby and Stella hit the road to find him—with a lot more than fifteen questions.

And after three thousand miles, a stowaway relative and hitchhiking teen lovebirds bound for an Elvis wedding chapel, the Miller sisters might get some answers.