Darkness falls - Franklin W. Dixon

The Hardys have come to the Hawaiian Islands to join in a scientific research project at the Mauna Kea Observatory. They have won the chance to witness a once-in-a-lifetime event - a total solar eclipse. But at the very instant day turns to night, the excitement suddenly turns deadly and the boys find the expedition leader, murdered. Frank and Joe begin there own research project and make some shocking discoveries - the expedition has long been plagued by personal hatred, professional jealousy and financial greed. Clearly evil lurks in the shadows and more violence could errupt at any moment.