On July 25, 1963, assistant director Kazuaki Yukawa introduces a documentary about an upcoming Daiei film. At the company's first meeting, producer Shigeo Nagano, stresses the need to come up with a fresh idea to complement their existing franchises. Special effects director Yonejiro Tsukaji suggests a lavish
kaiju movie. CEO Yuichi Nagano is impressed and approves it, although director Mitsuo Muraoka points out that
one of their competitors just released its own
kaiju movie. Tsukaji and Yukawa, tasked with deciding what kind of monster should star in the film, visit a zoo in Tokyo. However, none of the animals appeal to them. After Yuichi watches a movie featuring birds, he suggests that the monsters should be based on mundane animals. He and Tsukaji settle on rats and announce their decision at an August 5 meeting. The title will be "Giant Horde Beast Nezura", featuring a group of gigantic rats as its premise. Muraoka is skeptical that the rats will cooperate, so Tsukaji agrees to shoot some test footage. Daiei begins filming test footage on October 10, but the staff find controlling the domesticated rats and decide to use wild rats instead. Tsukaji captures wild rats in downtown Tokyo, which succeed as expected. Yuichi is delighted with the footage and allows the project to proceed, with Muraoka assigned as the director and Tsukaji as the special effects director. Tsukaji meets with sculptor Takiyama to commission a human-sized Nezura prop. Yuichi records a public announcement of the film, which is scheduled for a January release. To keep up with Muraoka's insistence on sets covered in rats, Daiei offers the public ¥50 for every rat they bring in. Cages of the animals soon fill a small warehouse. Takiyama completes the prop, and Daiei staff create a Mammoth Nezura puppet as well. The film's actors, including Utsumi, Michiko Ogata, Junko Kamei, and Schmidt, assemble for a
table-read. Screenwriter Hasebe's story features the United States and the Soviet Union announcing a joint lunar expedition. Mikami Space Laboratory's experiments on rats, intended to create a new type of space food for the astronauts, instead produce ravenous monsters. The Nezura escape the lab and rampage through Tokyo. A Mammoth Nezura emerges and battles the smaller rats, with the
JSDF ultimately killing them all. However, the rats eventually become infected with fleas and disease, with many crew members forced to wear masks in filming. Tsukaji watches a televised interview between a famous special effects director and his son Azuma, who agree that the public's attention has shifted from film to television, and Tsukaji's mood sours further. Citizens living near the studio interrupt the shoot on October 25 in protest, concerned about the rats spreading disease. On November 3, Daiei receives a stern letter from the Bureau of Social Welfare and Public Health recommending the termination of the film and the rats. A morose Yuichi complies. After Tsukaji immolates the rats the following day, he stands silently amidst one of the sets, then crushes one of the buildings in a fit of rage. Yukawa reflects in his documentary that even though Giant Horde Beast Nezura was a failure, it taught him a lot about filmmaking. Yukawa visits Yuichi, who has been in poor health, at his home on January 3. The CEO happens upon a small spinning firework and Yukawa offers to light it. The firework's motion gives Yuichi an idea for
a new monster spinning through the sky, and they rush off to Daiei to get to work. == Cast ==