When sun storms periodically swept Mercury with waves of solar fire, radiation and electricity, it was usual for the authorities to order evacuation of the small mining communities on the side of the planet that faced the Sun. But as time for the most violent solar eruption known to earthlings approached, no rescue rocket ship appeared outside the Sigma dome that housed Dick Rogers and his family. Around one of the universe's most awesome events - sun spots - Lester del Rey has written a tale of rugged courage and heroism in the face of impending doom. Young Dick Rogers wasn't too well liked by the townspeople. He insisted on keeping an erratic "wispy" - the strange form of Mercury life that took the shape of an electrically charged ball of flame - as a friend. And though Dick's favorite "wispy," Johnny Quicksilver, could usually be trusted, the mining engineers were never sure whether it was he who periodically blew out fuses and upset delicate electrical circuits. Against this background, the story of Dick Rogers' odyssey through Mercury's bleak and blazing landscape takes on desperate urgency. How he, an ancient robot and the Mercury veteran "Hotside Charlie" withstand Mercury's 800 degree temperatures, escape rivers of molten lead, and fight the planet's horrifying silicone beasts, is in the best science fiction tradition.