Still reeling after the hard-fought battle to repel Legion, Japan is now reminded of a deadly foe from the past. The Gyaos have returned, and this time the ornery man-eating birds have not only increased their numbers, but also added a menacing new member, Iris, to their destructive little club. Raised by a young girl whose parents Gamera accidentally squished, the flying blood-sucking squid monster Iris takes her learned hatred and goes out on the warpath. Dr. Nagamine and Inspector Osaka are reunited to help Gamera in his relentless quest to protect and save the human race. Can Gamera ground the Gyaos? Can the turtle tie up the terrible tentacles? Do the hapless humans and the rowdy reptile have what it takes to thwart the revenge of Iris?