
When the "sisters" go to Greece and Tibby dies unexpectedly, Bridget leaves Eric, and soon after finds out she is pregnant with his child. She wants to settle down with him and get married, but a part of her is restless. Ten years following the last sisterhood book, Bridget now lives in San Francisco, California with her longtime boyfriend, Eric.

They start writing to each other again and realizing she’s not afraid of his love, eventually end up together at the end of the book. As they talk, they rekindle a friendship. Lena goes back to Greece for a reunion with her friends and after discovering Tibby died, she asks Kostos for help with Tibby’s death. Ten years into the future, Lena is an art teacher at the Rhode Island School of Design, casually dating a sandwich maker named Drew, and still obsessing over Kostos. Her final gift to Lena, Carmen, and Bridget is willing them to move on and follow their hearts because life is too short to waste. It is later revealed that she discovered she had the disease when she found she was pregnant with her daughter Bailey whom she had with Brian. When she invited the girls to Greece she was going to reveal this and give them letters to help them move on. It is revealed through the novel that Tibby was suffering from Huntington's disease and aware that she was going to die, even though her death by drowning was an accident.

Disaster strikes when she suddenly dies in a swimming accident on the shores in Greece leaving her friends, Lena, Bridget, and Carmen, devastated, and with the belief that she committed suicide, they begin to questioning everything that they believe in. Nearly two years after giving birth to her daughter, Bailey, she calls her friends together for one last trip to Greece. Soon after moving to Australia, Tibby learns that she is not only pregnant but she is also diagnosed with a terminal disease. Ten years following the last sisterhood book, Tibby has moved to Australia with Brian and now has almost no contact with the three other girls.

This is the fifth book in The Sisterhood of the Traveling Pants series.

The story concludes the adventures of four girls who share a pair of "magical" pants that fit each one of them perfectly, despite their vastly different shapes and sizes. Sisterhood Everlasting is the fifth and last novel in Ann Brashares's "Sisterhood" series.
