Where there is light, there is shadow. Beyond the millions of stars of the Milky Way, above the nations, politics and the conflicts of the people who live there, a force is operating. You cannot search for them. If you knew their secrets, you'd be dead. You cannot use them because you are the one being used. The overlords are ruling the universe. Even their existence is not confirmed, but people call them Shinobi...
In Space Ninja, the players command a group of Shinobi (Ninja) and try to manipulate the people of various planets. The game has four rounds. Each round, players decides which planet to send two of his/her shinobi to. Every planet has an independent government and individual powers and the planets interacts with each other in terms of population growth or decline. You can send out Shinobi to interfere with the politics on the planet and gain points by influencing them. At the end of each round, each planet's effect will be resolved, affecting its population, before scoring occurs. The top two player-factions with the most control (majority) will score according to the population. Each planet is scored sequentially. After 4 rounds and sending 8 Shinobi per player, the game is over. The player with the most points wins the game.