Despite Christoff and the Monster Girl Defense Force's great victories, the war to save this new future isn't over yet. It's now a race around the world to distant horizons, a race to save the keys that could end... or save... the world from the vilest monster the world's ever seen!
But when an army of giant monsters rises to threaten a new apocalypse, Christoff will need more than his own power or the MGDF. To save the world, he'll have to unite it under one banner.
Story is ok, honestly only the first one was interesting and engaging. 2 and 3 where kind of boring. Characters just running to places and constant uninteresting harem additions. This one is pretty much copy of the last one. There's not a much substance in the story.