While out on vacation in outer space， Mr. and Mrs. Satomura stumbled upon the existence of the evil organization called “Yegirl，” and to prepare for the day when the Yegirl military forces attack Earth， they have created a set of special armored suits for their children to fight as the “Forcemen.” Now， Yegirl’s invasion has started， and the Forcemen fight to protect the peace of Earth. The eldest daughter of the family is Kazuna Satomura and she becomes Force Pink when fighting the enemy. She engages in a fight with formidable TigerChameleon， who suddenly disappears in the middle of the battle. In fact， TigerChameleon is aiming his TigerArrow at Force Pink. Just when the arrow is shot， Kazuna’s sister Sorami， Force Yellow， stands in front of Kazuna to protect her. The arrow hits Force Yellow and she falls downstairs. TigerArrow is the only one who knows how to pull out this deadly arrow， so Kazuna， telling her brothers to take good care of their wounded sister， sets out for the enemy lair alone. The arrow dug deep into her body slowly moves close to her heart. There is not much time， so Sorami bends her knee to TigerArrow， and swears she will do anything to save her life. Kazuna and Sorami are not really related by birth， but rather by their love for each other， deeper than the love between real sisters. Because of Kazuna’s tactics Sorami manages to get through this predicament， but she is attacked by ShrimpFroggy， Yegirl’s monster the girls have defeated， and the creature has become enormous now. Sorami， gifted with mysterious powers， gives Kazuna her powers and Force Pink becomes enormous， too. Can she protect her beloved siblings and peace of Earth from evil?