A black rabbit named Black Asobin takes over Sehagaga's network and steals almost all of the girls' medals, challenging them to enter his world and get them back. After battling their way through Black Asobin's tower, Saturn, the only girl with a medal remaining, enters the world of Space Harrier and defeats Black Asobin, who is revealed to have been Center all along. For clearing the 'graduation exam', the girls gain 20 medals each, giving Dreamcast and Mega Drive more than enough medals to graduate. Saturn, being three short, is nearly forced to be held back, but Dreamcast and Mega Drive share their spare medals so she can graduate alongside them.
順調に単位メダルが貯まり、そろそろ卒業が見えてきたある日、ドリキャス、サターン、メガドラの前に“ブラックアソビン”と名乗る敵が現れる。単位メダルを奪われてしまった3人は、ブラックアソビンを追ってブラックアソビンワールドへと向かう。そこで3人を待っていたのは、バーチャファイターのリングと、見覚えのある一人の青年だった。
