Sharon Smith is a senior in high school and the valedictorian of her class. She plays the cello and piano, volunteers at the library, tutors other kids, works part time at McDonald's, and has been running her paper route since she was eight.

On top of all that she is taking college credits online, saving to buy a car, and applying to all the Ivy League colleges, but what matters the most to her is her bestfriend and next-door neighbor, Calvin. They've known each other for forever, and she imagines spending the rest of their lives together. If only he wasn't obsessed with Sharon's fraternal twin, Shannon.

Shannon is everyone's favorite. She sings like the angels, is usually smiling, has golden blonde hair, chocolate brown eyes, and is always the center of attention. She's not the smartest, but has been given a free pass in life because of her severe congenital heart defect.

She has the rarest blood type in the world, which complicates getting a much needed heart transplant.

Because of this, she sucks up all her parents' attention, and is in the hospital more than she is out of it, leaving Sharon alone most of the time. Sharon isn't completely alone though. She has her maternal grandparents.

Someone Else follows the twin's last year of high school, the ups and downs of love, family drama, and trying to make a plan for the rest of their lives. They may not end up where they want to be, but fate puts them where they need to be.