With a bit of last summer's sand in the pockets, the Traveling Pants and the Sisterhood that wears them embark on their 16th summer. Bridget: Impulsively sets off for Alabama, wanting to both confront her demons about her family and avoid them all at once. Lena: Spends a blissful week with Kostos, making the unexplainable silence that follows his visit even more painful. Carmen: Is concerned that her mother is making a fool of herself over a man....

As their lives take them in different directions, Lena, Tibby, Carmen, and Bridget discover many more things about themselves and the importance of their relationship with each other.

Now that they are all grappling with their adult lives, the four friends have little time to stay in touch -- until Tibby proposes the four gather for a reunion in Greece. Before the Greece trip begins, however, one friend dies -- leaving the remaining three devastated. As they struggle to make sense of their loss, they come to realize that, even in death, friendship is everlasting.