Libby Lost and Found by Stephanie Booth

Meet Libby Weeks, author of the mega-best-selling fantasy series, The Falling Children—written as "F.T. Goldhero" to maintain her privacy. When the last manuscript is already months overdue to her publisher and rabid fans around the world are growing impatient, Libby is diagnosed with early-onset Alzheimer's. Already suffering from crippling anxiety, Libby's symptoms quickly accelerate. After she forgets her dog at the park one day—then almost discloses her identity to the journalist who finds him—Libby has to admit she needs help finishing the last book.

Desperately, she turns to eleven-year-old superfan Peanut Bixton, who knows the books even better than she does but harbors her own dark secrets. Tensions mount as Libby's dementia deepens—until both Peanut and Libby swirl into an inevitable but bone-shocking conclusion.