The year is 1909. Bankrupt businessman Julius Bedford is going nowhere - until he meets the eccentric scientist Professor Cavor. Because Cavor has invented an extraordinary substance. Anything it touches becomes lighter than air! Together, the two men devise a wild scheme. Why not go to the Moon? But the lifeless world isn't quite as dead as it seems. Soon Bedford and Cavor are pitched into a thrilling struggle deep beneath the Moon's surface and an encounter with its terrifying alien masters – the Selenites!