Lena, Tibby, Carmen, and Bee have just finished their first year of college, and are hoping for some time together. As in summers past, that doesn't work, and they rely on the pants to keep them together as their worlds are rapidly changing. Bee is upset to find that her boyfriend, Eric, is going to teach at a summer camp in Baja without her; as a way to get back, she signs up for an archaeological dig in Istanbul- finding more than just "ancient dirt." Tibby is trying to find out if Brian is the one. After a rough summer start, she breaks things off with Brian in search of answers, while also staying for a summer class at NYU. Lena is still trying to forget about (forgetting about) Kostos, by having a summer fling with a boy in her summer art class. Carmen is the September having the hardest time dealing with change; the girls' first year of school separated was brutal to her. She, in turn, goes to theater camp for the summer to try and find out who she really is. Forever In Blue takes the girls on their own personal journeys; it questions how far they want to go in life, and for how long they want their friendship to last. As the last summer with the pants comes to a close, Tibby, Carmen, Bee, and Lena come together to realize that their friendship, with or without the pants, will be never ending.