14-year-old Abbey's ability to talk to ghosts has saved both friends and strangers in need. But it's also attracted the wrong sort of attention. That attention arrives in the form of a domineering federal agent who insists that Abbey help her with something dangerous. She tells the story of a roguish fellow, Manfred Krug, who traveled the world as a fabled trader in the 1920s. As his diary details, Krug returned from Shanghai with artifacts holding the power to gather and focus otherworldly energy. The agent warns that if the relics fell into the wrong hands, it would be a disaster of biblical proportions. Enlisting her ride-or-dies, Abbey, Kelly, and Lexi search some of the most haunted places in Minnesota. But someone else-someone dangerous-is after those same artifacts, and they're right behind Abbey and her spook squad.