An abandoned rock quarry, mysterious flying objects, and a valuable deposit of titanium lead the five Hollister children--Pete, Pam, Ricky, Holly, and Sue--into their latest thrilling adventure. When a package of instruments from a weather balloon is parachuted onto their front lawn, the Hollisters are baffled and very excited. Just what is the meaning of the orange parachute and its dangling white box? The Hollisters connect the balloon...