An ancient prophecy says: when all the Gates connecting the Big and Small Midgards are closed, the End of the World will come. The Last Gate must be opened at all costs, otherwise the destruction of the world is inevitable. Its first signs have already appeared: rain of giant frogs falls on people, earthquakes destroy cities, a terrible flood destroys the last hope of salvation. But a way out is found - the schoolboy Heinrich, the Hero of Little Milgard, falls into the hands of an ancient scroll, which tells about where to look for the Last Gate. And now the Knight-Hero and his friends must hurry before the water swallows the entire Earth!