Franklin W. Dixon 
Into Thin Air 

When the daughter of an amusement-park owner goes missing, its anything but fun and games in this Hardy Boys adventurea new take on the classic series.Daisy Rodriguez is missing. Just like that, gone without a trace. Her father, Hector Rodriguezowner of Funspot, Bayports local amusement parkis frantic. He feels hes to blame, since Funspot was recently the location of another disappearance. Could Daisys vanishing be somehow connected? Joe and Frank Hardy figured out the first Funspot mystery and are up to their necks in this one, too. Daisy doesnt seem to have an enemy in the world; no one has a bad word to say about her. So who in Bayport wants this girl gone?