Sometimes a promise becomes a prison. Fearing eternal singledom, childhood friends Kate and Paul made a vow that if they didn't find love by thirty, they would marry each other. Years later, about to celebrate their 10th wedding anniversary, Kate and Paul start to wonder, will this be their last? Is friendship really enough to make a marriage? As Kate struggles with a secret that reaches far into their past, the couple's vow has become the very thing that threatens their future