H.G. Wells wrote about the war of the worlds. But what if the aliens are good? How will this change earthly society? Especially if it is prehistoric, and someone else rides dinosaurs, and someone is forced to hide from them... was forced. Rapid progress brings happiness...? Fate will throw the hero from the serene life of the capital, through the crucible of civil war, into the fairyland of the elves. Doctor's knowledge and mechanic's skills help in adventures. But he is destined to return no earlier than the aliens leave his home planet. This is pure steam-punk according to all the canons of the good old genre and without any impurities. If you liked Jules Verne and H.G. Wells, you will definitely like this novel.