Ellen loves Link and James. Her older brother and his best friend are the only company she ever wants. She knows they fight, but she makes it a policy never to take sides. She loves her brother, the math genius and track star. She is totally, madly in love with James, his face full of long eyelashes and hidden smiles. “When you grow out of it,” James teases her, “you will break my heart.” Then someone at school asks if Link and James might be in love with each other. My Heartbeat is a fast, furious story in which a quirky triangle learns to change its shape and Ellen, at least, learns the limits of what you can ever know about whom you love.