When Nube and his class arrive at a small island to carry out beach activities, they heard a forbodding tale from an old man residing on the island. Legend has it that there is a creature known as the sea spider in the open seas around the island. When the creature is past 200 years old, it will turn into a monster and devour humans to satisfy its appetite. However, curiousity kills the cat and Yukime decides to pursue the authenticity of the legend. And then, a girl suddenly appears on the beach. Possessed with a strange charm, she immediately attracts Hiroshi's attention and overcomes him. Soon later, strange things start to happen to the others whereby Kyoko and Ritsuko-sensei got attacked under strange circumstances. The true identity behind the mysterious girl is questioned and the legend behind the sea creature seems to be true after all.

Kumiko Ijima is a very timid girl who happens to recognize a murderer still in pursuit at a park. With the help of her friend Kyoko Inaba, she warns the police about the wanted man. After trying to escape the police by car, the murderer crashes and ends up in the hospital. Some time later, a mysterious entity starts to terrorize the neighborhood in search of a girl who has the name initials K.I. and uses a red ribbon on her hair.

When the 5 richest and most powerful girls at an exclusive private high school are sent a death threat they decide to take matters into their own hands and bring divine retribution to their would be assailants. Using their collective resources and skills they show the terrorists that they messed with the wrong girls.