In the year 2119, the Greensleeves, a spaceship investigating the existence of extraterrestrial life, encounters the rogue planet "X-23." After they discover traces of destroyed high-level civilizations on planets that X-23 had passed by, the World Federation orders the Greensleeves to destroy X-23. However the captain of the ship, Professor Sugita Isao, refuses the order and all communications are cut off. Two years later, the eldest son of Professor Sugita who lives in the science academy town Nagisa City, is suddenly lead to Phoenix Tower, an integrated health and science research institute. The leader of the special medical team "White Pegasus," Dr. Miya, requests he joins them. One after another of the citizens of Nagisa City fall ill for unknown reasons, and then are treated by a special vessel called the "Wonder Beat" which is miniaturized and inserted directly into the affected area. And that is how the battle begins between the White Pegasus Team and the mysterious aliens who keep attacking them.