The latest novel in Ben Bova's acclaimed Grand Tour of the Solar System, the story of humankind's first steps to explore Earth's closest neighbours in the universe. The closest planet to the Sun, Mercury is an airless, heat-scorched world where temperatures rise to four times higher than the boiling point of water. But this vision of hell is also a planet with unlimited solar power - worth a fortune to the space tycoon Saito Yamagata if he can find a way to harness it. He has hired the enigmatic Dante Alexios to establish a research station on the surface of the planet and find a way to turn that solar energy into portable power satellites. But Yamagata is secretly also preparing the way to a very different dream: he wants to travel to the stars themselves. And Alexios has his own obsession, a plot to lure an old enemy to this hellhole of a world and take his revenge for one of the worst disasters in human history.