Bernie Magruder and the Parachute Peril

Life in Middleburg is mighty strange these days -- a mysterious building is going up in the next town over and Bernie's absentminded sister, Delores, shocks everyone by devoting her life to a career in parachute-making. But when Delores is summoned to jump from a plane wearing one of her own parachutes, Bernie and his friends smell trouble. Who would volunteer Delores for such a stunt and just who "is" that suspicious guy hanging around the new building?