Aspiring choreographer Sophie Orenstein would do anything for Peter Rosenthal-Porter, who's been on the kidney transplant list as long as she's known him. Peter, a gifted pianist, is everything to Sophie: best friend, musical collaborator, secret crush. When she learns she's a match, donating a kidney is an easy, obvious choice. She can't help wondering if after the transplant, he'll love her back the way she's always wanted.

But Peter's life post-transplant isn't what either of them expected. Though he once had feelings for Sophie, too, he's now drawn to Chase, the guitarist in a band that happens to be looking for a keyboardist. And while neglected parts of Sophie's world are calling to her--dance opportunities, new friends, a sister and niece she barely knows--she longs for a now-distant Peter more than ever, growing increasingly bitter he doesn't seem to feel the same connection.

Peter fears he'll forever be indebted to her. Sophie isn't sure who she is without him. Then one heartbreaking night twists their relationship into something neither of them recognizes, leading them to question their past, their future, and whether their friendship is even worth fighting for.