Mattie Gokey has big dreams of one day going to college, but little chance of realizing them. She has to stay behind and protect her sisters and entire family from financial ruin. Desperate for money, she takes at the Glenmore, a hotel for high class people vacationing nearby. There, hotel guest Grace Brown entrusts her with a packet of letters to burn for her. But when Grace’s drowned body is discovered in the lake, Mattie realizes the letters could reveal the dark truth behind a murder.