"Union" is a multiplayer online role-playing game that was once popular. A team called "Pleiades" composed entirely of elementary school students is the overlord of the game, invincible and unbeatable. However, an accident caused the death of one of the members of the group, Asahihime (voiced by Omori Higashi), which led to the disbandment of the Pleiades and the game was forced to go offline. In a blink of an eye, many years have passed, and the former members of the Pleiades have now become high school students. At this time, a game called "Reunion" has once again entered people's sight. The former forward of the Pleiades, Tian Yu Yang Xiang (voiced by Takanari Kengo), logged into the game and accidentally found Asahihime in the game. Standing in front of him, is it just a piece of information or the ghost of a childhood sweetheart? In order to fulfill a childhood promise, the Pleiades gathered together again.