Salamanca Tree Hiddle takes a long car trip from Ohio to Idaho, to see the bus her mother crashed and died on. She decides to tell her grandparents about her friend Phoebe. Phoebe receives a message from a (so-called) lunatic. Then Phoebe must try to deal with the disappearance of her mother. Salamanca doesn't realize it at first, but beneath Phoebe's story is her own.