Drug overdoses don't happen to girls with good grades and athletic prowess, with longtime friends and a devoted boyfriend. Or do they? When high school seniors Cassidy and Sarah, along with Kayla's boyfriend Paul, discover their best friend Kayla unconscious at a party, the idea that they have lost her to a heroin overdose is unbelievable. She didn't use drugs, except the pain medicine prescribed for a soccer injury, and she had no reason to accept any from a stranger. The month that follows her death is filled with anxiety, sadness, frustration, and questions. Answers won't bring Kayla back, however, so as Cass and Sarah struggle with the insensitive but predictable behavior of parents, classmates, and teachers, Paul falls into a depression that leads him down a dangerous path. With Kayla's younger sister Mia in mind, the three of them work towards forging ahead without the girl who has held them together since elementary school.