In the great tradition of science fiction, as represented by the best works of H.G. Wells and Jules Verne, "The Invincible" describes the story of a space cruiser that has been sent to a mysterious planet to investigate what happened to another spaceship, whose communication with Earth was suddenly interrupted. On Regis III, Navigator Rohan and the rest of the crew are faced with the classic dilemma: what kind of energy can man choose when his knowledge is limited? The issue of the inexplicable, the paradoxical, the problem that is beyond the possibilities of analytical interpretation are intertwined in a plot of science fiction, where the suspense is maintained - and escalated - until the end.