On some planets, Mark finds himself in danger. * * * Mark lives in a small northern, industrial town, with his mother. Their life depresses them. They bully Mark at school. Destiny throws Mark into an unbelievable world. On planet after planet, he finds staggeringly queer lives, but the aliens welcome him. Sometimes, he fights for his life - and to save alien lives too. Planets clash so much with what he was used to, he could be dreaming. But he is not dreaming. They follow UFOs to their home planet. There, the Dreadful 5000 are meeting - they say Earth is a murderous planet and they must kill all humans. Mark calls for help. Some 70,000 spaceships come into the sky overhead - so well do they know about him over thousands of light-years. Mark comes back to finish school. In the holidays, Ethelinda picks him up to take him back into very deep space.