Off the coast of Japan, the environment has been ravaged with poisonous starfish-like creatures called Barem. Meanwhile, the Elias sisters, Moll and Lora, survey the destruction and enlist the help of three children, who had just discovered and befriended a strange little creature dubbed "Ghogo" to help find the mysterious treasure of Ninai Kanai, an ancient lost civilization, to save the Earth from the declining environment.
The Elias then tell the children that the people of Ninai Kanai created a monster called Dagahra as a method of pollution management gone wrong and only Mothra Leo can stop it; however, he will need the help of the lost castle of Ninai Kanai itself and the mysterious treasure within. Belvera, the evil Elias sister, manipulates two fishermen and wants the treasure of her own. They all journey to the lost castle, hidden beneath the ocean waters and it magically rises out of the water after the travelers discover it.
Dagahra, awakened after a sudden increase in pollution levels, then releases a swarm of Barem into the sea, killing many types of sea life.
Inside the temple, Moll, Lora and the three kids attempt to find the treasure, while Belvera and the two controlled fishermen try to thwart their mission. After stealing some jewels they've found, the fishermen inadvertently unlock a gateway and awaken the Princess of Ninai Kanai. The Princess tells the three Elias sisters that Earth must be protected and saved, that the children are the hope of future generations and reveals that Ghogo is the lost treasure.
- Lora as Sayaka Yamaguchi
- Moll as Megumi Kobayashi
- Aki Hano as Belvera
- Shiori Uchiura as Hikari Mitsushima
- Kohei Toguchi as Masaki Otake
- Yoji Miyagi as Shimada Maganao
- Fisherman #1 as Atsushi Okuno
- Fisherman #2 as Hajime Okayama
- Yuna as Nonami Maho
Blu-ray Sony (Toho Godzilla Collection)
- Aspect Ratio: 1.85:1 (1080p) [AVC]
- Soundtrack(s): Japanese and English (DTS-HD 2.0 Stereo)
- Subtitles: English, English SDH and French
- Theatrical Trailer (1080i, 1:55)
- Teaser 1 (1080i, 0:31)
- Teaser 2 (1080i, 0:39)
- Teaser 3 (1080i, 1:05)
- Notes: Comes with Rebirth of Mothra and Rebirth of Mothra III. This film shares a disc with the third film, while the first has its own.
- Released: February 1, 2000
- Directed by Kunio Miyoshi
- Written by Masumi Suetani, Tomoyuki Tanaka
- Produced by Hiroaki Kitayama, Shogo Tomiyama
- Music by Toshiyuki Watanabe
- Cinematography by Yoshinori Sekiguchi
- Edited by Miho Yone
- Production Design by Tsuyoshi Shimizu
- Assistant Directing by Masaaki Tezuka
- Special Effects by Koichi Kawakita, Kenji Suzuki