Helen and Enola plan to escape with Gregor ( the Atoll 's astrologer\/engineer ) in search of Dryland . The girl and her caretaker , Helen ( Jeanne Tripplehorn ) , the atoll 's shopkeeper , plan to escape with Gregor ( Michael Jeter ) , the atoll 's expert on hydroelectric power and resident astrologer and inventor , in the hopes of finding Dryland . Unfortunately , Gregor 's escape method , a hot air balloon made of old rags , launches too early with him on it , leaving Helen and Enola stranded .