"Many centuries ago, three carefully-selected young Earthlings were transported from their native lands to my faraway world. Here they were granted astounding powers, and eternal youth then returned to Earth, their mission to watch over the human race, helping the good in it to survive and flourish. In the course of history, their names have become legend: Hercules, empowered with the strength of a hundred men; Astrea, able to assume any living form; Mercury, the amazing athlete who can match the speed of light. Working together with me, Sentinel One, and my maintenance robot, Mo, these teenage guardians form the greatest team the world has ever known: the Space Sentinels." - introduction