Having left her elite Manhattan private school to attend an equally exclusive New York State boarding school, sophomore Jenny Humphrey sets out to become the most alluring girl on campus.

In the summer following high school graduation, Blair heads off to London with her English Lord boyfriend, Serena prepares to star in a remake of "Breakfast at Tiffany's," Nate heads to the Hamptons, and Dan and Vanessa rekindle their love.

Only two weeks remain until graduation and there are more than a few surprises in store for the senior girls at an exclusive private high school in New York City, as they fill their last days together with boys, gossip, parties, and shopping.

At the dawn of the twentieth century, several families in New York remain stunned by the antics of mischievous socialites, including Henry, Penelope, and Lina.

In 1899 Manhattan, the drowning of beautiful Elizabeth Holland, daughter of New York society's ruling family, brings to the surface the scandalous behavior of several teenagers of varying social class.

As graduation approaches, Anna finds herself attracted to her father's intern and unsure of Ben, Cammie learns more about her mother's death, and Sam tries to win back Eduardo and find her mother.

Diana and Elizabeth Holland, two of Manhattan's favorite socialites, show new signs of maturity as Elizabeth tries to deal with a secret from the past, and Diana is forced to make a decision about her future; meanwhile, Carolina finds that money can buy happiness, and Penelope learns the pleasures of life without Henry.

Schuyler Van Alen, growing comfortable with her newfound vampire powers, seeks her grandfather in Italy, while back in New York plans are being completed for the fabulous Four Hundred Ball, to be followed by an elite, teens only event at which masks hide a terrible secret.

Owen, Avery, and Baby Carlyle have made both friends and enemies in Manhattan, and after Owen steals his best friend's girlfriend and Avery claims the popularity crown, a socialite war rages with rumors as weaponry.