Thirteen-year-old Jack knows what cured his baby sister when his family thought she might never get well—Dr. Kingsbury’s “Miraculous Tonic.” Guaranteed to relieve maladies known to man or beast, Dr. Kingsbury’s potion can cure everything from pimples to hearing loss to a broken heart, and Jack himself is a witness to the miraculous results and the doctor’s kindness. When he had no money, the doctor didn’t turn him away but gave him the tonic for free along with a job—to travel with him from city to city selling his cure-all elixir. When Dr. Kingsbury and Jack arrive in Oakdale, the town at first feels like any other they’ve been to. But it’s clear Oakdale is a town with secrets, and its citizens are slow to trust strangers. Then Jack meets Cora, and a friendship neither expected starts to bloom. Together they uncover something else they didn’t expect—not only secrets about the town but also Dr. Kingsbury. As they race to discover the truth, they’ll have to decide who and what to believe before it’s too late.