A sequel to the 1980 movie The Legend of the Stardust Brothers. As well as being a rock musical comedy, it also borrows elements from other genres such as road movies, westerns, and meta fiction.

When a massive, gilled monster emerges from the deep and tears through the city, the government scrambles to save its citizens. A rag-tag team of volunteers cuts through a web of red tape to uncover the monster's weakness and its mysterious ties to a foreign superpower. But time is not on their side - the greatest catastrophe to ever befall the world is about to evolve right before their very eyes.

The only movie theater on the Onomichi seafront is about to close its doors. Its last night of screenings will be an all-night marathon of Japanese war films. When lightning strikes the theater, three young men in the audience find themselves thrown back in time into the world inside the screen.