EDITOR’S NOTE: Atragon was on Chiller Theater on Saturday, November 4, 1967 at 11:20 p.m. It also aired on August 14, 1971 and July 1, 1972.

In Japan, this movie is known as Kaitei Gunkan and is a combination of two books, The Undersea Warship: A Fantastic Tale of Island Adventure by Shunrō Oshikawa and The Undersea Kingdom by Shigeru Komatsuzaki, who did design work on the film (he also was part of The Mysterians and Battle In Outer Space).

The lost continent of Mu has reappeared — justified, ancient and with its own sun — and threatens the entire world. The only man who can save us all is Captain Hachiro Jinguji (Jun Tazaki), a WW II naval commander who everyone thinks is dead but who has been working on a super submarine he calls Gotengo (Roaring Heavens). He refused to surrender at the end of the war and he certainly won’t to the Mu.

He refuses to help — the ship is only to bring Japan back to power — until the Mu kidnap his daughter Makoto (Yōko Fujiyama). That’s when he goes on the attack with Rear Admiral Kusumi (Ken Uehara) and decimates the empire of the Empress of Mu (Tetsuko Kobayashi), who chooses to swim into an explosion instead of giving up.

Directed by Ishirō Honda, this was Toho’s big movie of 1963. It was so popular that it was re-released five years later as the double feature with Destroy All Monsters. It was released in the U.S. by American-International Pictures as a double feature with The Time Travelers.

The Gotengo shows up in the TV series Godzilla Island, as well as Godzilla Final Wars, Super Fleet Sazer-X the Movie and the web show Godziban. There was also a two-episode OAV anime, Super Atragon. The monster Manda appears in Destroy All Monsters.

You can watch this on Tubi.