Kelsey Callahan is smart, tough and fiercely loyal to her friends. She wants nothing more than to follow in her father's footsteps and become a detective just like her hero, Sherlock Holmes. A natural leader, problem-solver and lover of mysteries, Kelsey finally gets the chance to solve a mystery of her own when Ethan, a cute but enigmatic loner, appears in her class. At first mildly infatuated with him, she becomes even more fascinated by his behavior: namely, that he dresses like a "bad boy" but doesn't act like one. As her friendship with Ethan deepens, Kelsey soon learns that there are events at play in Ethan's life that are both tragic and dangerous: events that, the deeper she digs, could end up threatening not only their relationship but their very lives.