As Ulti Ace, an alien protecting Earth from the far reaches of space, she normally commands the Earth Defense Force as Captain Yurihoshi Yurina. However, due to the betrayal of a subordinate who secretly harbors sexual desires for Captain Yurihoshi Yurina, she transforms into Ulti A and finds herself in dire straits while battling a giant monster. It was all a trap set by the Dark Demon King (Giant Human Chair), who preys on human desires. Thus, the giant heroine Ulti A becomes an outlet for the sexual desires of the invading aliens and humans, forced to experience pleasure by the Dark Demon King (Giant Human Chair), and violated until she rots away in depravity...