 Ten years ago, Japan was attacked by a strange unstoppable creature which was later called a Hedrodyne. It took a great deal of sacrifices and loss of life to stop the creature. A private company builds a giant robot that was called Dia-Guard. But not another creature appeared for 10 years and Dai-Guard becomes more of a joke then the protector of the city. Until the day a new Hedrodyne raises his ugly head. Against orders three PR officers steal Dai-Guard and now are our only help to protect the city against this new wave of Hedrodyne attacks.