Aldeans were a people from the planet Aldea. The planet was long thought to be a legend after the Aldean Progenitors cloaked the planet in 3000 B.C. (Last Unicorn RPG module: All Our Yesterdays: The Time Travel Sourcebook) The cloak would cause sterility in the entire population. In the 2360s, the Aldeans revealed themselves to the USS Enterprise crew and abducted some of the Enterprise crew's children in an effort to prevent their own extinction. (TNG episode: "When the Bough Breaks")