Carmen decides to discard an old pair of jeans, but Tibby, Lena, and Bridget think they are great and decide that whoever the pants fit best will get them. When the jeans fit everyone perfectly, a sisterhood and a memorable summer begin.

The members of the Sisterhood of the Traveling Pants graduate from high school and spend their last summer before college learning about life and themselves.

Despite having jobs and men that they love, Tibby, Lena, Carmen, and Bridget know something is missing: the closeness that once sustained them. Carmen is a successful actress in New York, engaged to be married, but misses her friends. Lena finds solace in her art, teaching in Rhode Island, but still thinks of Kostos and the road she didn't take. Bridget lives with her longtime boyfriend, Eric, in San Francisco, and though a part of her wants to settle...