"Jane and Marnie have been inseparable since they were eleven. Growing up, they shared everything, they knew the other's deepest secrets, and they wouldn't have had it any other way. Jane was always happiest when it was just the two of them; in fact, she remembers those days as the best time of her life. And even when Jane married the man of her dreams, somehow, Jonathan only added to Jane's life, without subtracting from the perfect equation of her...