Sibling rivalry never looked so good.

Now that they're officially family, the Sloane sisters are stuck living together in an Upper East Side town house and sharing everything—from cute clothes to even cuter crushes. Is New York City big enough for all four of them?

Cate: The once and future queen bee of Ashton Prep is at war with her ex-besties. Cate's weapon of choice: the hottie next door. Because nothing says social dominance like serious arm candy.

Stella: London's former It Girl is tasked to recruit cool friends for her and Cate's new crew. Her mission: Make a nobody into a somebody. But will her protégée measure up? Or has Stella created a monster?

Andie: The petite beauty has what every girl wants: a crush who likes her back. Too bad he was stepsister Lola's crush first. Um, dibs!

Lola: The class klutz is defying her rep by embarking on a high-fashion modeling career. When she becomes the muse of the craziest man in fashion, will Lola end up runway worthy or style roadkill?

Style. Sabotage. Sisterhood.