The Jashinka Empire rises from the depths of the Earth to conquer the world. To stop them, Dr. Kyutaro Yumeno assembles five inventors to his laboratory, Yumeno Invention Laboratory and gives them the power to become Dynamen. Each member has their own goal, but as the Kagaku Sentai Dynaman, they are united to stop the Jashinka Empire in their tracks.

After botching his latest assignment, a third-ranked Japanese hit man becomes the target of another assassin.

When the Shogun Tokugawa III is in bed with a girl, she turns into a monster. The court believes she is Ninja Magic, used to frighten the lord off women so that there will be no heir. Tôma, a famous swordsman, is called in and exposes the Ninja, even discovering their leader, a beautiful young girl named Kagiroi. Guessing that she is the daughter of some ousted daimyo anxious to get back into favor, he is about to unmask her when he is taken prisoner...