Lilac Sophia Carpenter is sixteen years old. She's going to be sixteen years old for the rest of her life. Confined to her bed as her health declines, Lilac lives her life in daydreams, imagining her love story to her former best friend, Nathan Emery. But Lilac and Nathan haven't talked since that fateful night-the night of her sister's wedding, when her health worsened and his life unraveled and the already-fractured pieces of their friendship became irreparable. With the comfort of her daydreams becoming more and more elusive, Lilac must decide if reality can be greater than her own imagination when there's little time left for living.