Mrs. Bentley's Coloring Books

From the introduction: The Investigators have been contacted by Dr. Franklin Braziel, resident of the small Northern California coastal town of Wile’s Break. Over the phone, Dr. Braziel requests a meeting with the Investigators at a place of their choosing, saying only that it is a matter that only people of the character’s caliber can handle. At the meeting, Dr. Braziel informs the group that he is friends with, and doctor to, the Jacobson family. Over the past few weeks, Maggie Jacobson’s daughter, Sarah, has been struck with a fatiguing illness that no professional can pin down. The girl, once bright and lively, has become listless and gray. Barely able or even willing to eat, the only object that seems to give Sarah any sort of life is a coloring book that she stole from her day care center.