What is the main conflict in The Second Summer of the Sisterhood by Ann Brashares?

The Second Summer of the Sisterhood, by Ann Brashares, is a sequel to the author's earlier work, The Sisterhood of the Traveling Pants. The first book follows four teenage girls through their 16th summer and this novel picks up their lives as they begin their 17th summer. The girls are lifelong friends who also share a pair of pants as part of their bond.

As summer begins, Tibby Tomko-Rollins is heading to a nearby college where she will spend several weeks studying film, while Carmen Lowell and Lena Kaligaris stay at home in Bethesda, Maryland. Bridget Vreeland abandons her plan to stay at home when she finds several letters from her maternal grandmother, from whom her father has been estranged for many years since her mother's death. Bridget decides to go to Alabama to see her grandmother and look for answers that might help her reconnect with herself after a year of floundering.