The Latecomer - Jean Hanff Korelitzová

The Oppenheimer triplets have been reared with every advantage: wealth, education, and the determined attention of at least one of their parents. But they have been desperate to escape each other ever since they were born. Now, on the verge of their departure for college and so close to their long-coveted freedom, the triplets are forced to contend with an unexpected complication: a fourth Oppenheimer sibling has just been born. What has possessed their parents to make such an unfathomable decision? The triplets can't begin to imagine the power this little latecomer is about to exert--or just how destructive she'll be to their plans...