Yes, no sooner have we gotten a song from Akiko (Miki Yashiro), the starlet, the skies cloud over and open up, letting loose a torrential rain and high winds on the craft. The passengers take cover, realizing there is nothing they can do. They awaken to find themselves drifting through a dense fog, and eventually come upon a mysterious island, surrounded by that fog. They go ashore and begin exploring, knowing they are going to need food.
During their explorations, they see lots of mushrooms growing large and wild. They also find a grounded ship. They go aboard and find it is a research vessel, and it appears their work had to do with radiation. They also find a jar containing a large mushroom labeled "Matango" and a journal warning not to eat said mushrooms.
The group splits up into different jobs, mostly centering on food gathering. This is also when the social structure begins to break down. The film takes a turn from being about shipwrecked friends into Lord of the Flies territory. Everyone begins to argue; people begin looking out only for themselves. There is some discussion of the class divide between the wealthy and the working class, especially here in the wild, where the working class holds the true power. This lasts through the middle portion of the film.
As we start moving towards the conclusion, the trippier, surreal moments come into play as we get to see the mushroom people. Apparently, if you eat the mushrooms, you become a mushroom, and mushrooms love the wet climate of this hidden island. The survivors are still very much divided, but slowly they are each lured to the call of the mushroom, leading to full bellies and visions of nightclubs. The mushroom people, presumably crewmen from the research vessel, are very creepy looking, lumbering like zombies, but looking like big mutant fungi.
This final turn would seem to be a statement against drug use, and possibly a reaction to the horrors of nuclear power and radiation. For a time the film was banned in Japan as the mutant mushrooms bore a resemblance to victims of the nuclear bombs.
The film was directed by Ishiro Honda, who had previously made one of the best films dealing with nuclear horror with Gojira a decade earlier. This film works on a smaller, more personal level, but is still effective. Honda nicely builds tension through the film, as external elements take their cumulative toll on the victims.
Is it a great film? No, not really. Still, it is one worth the time, and is rather insidious in how it draws you in. Yes, it is slowly paced, but each stage brings with it new things to discover and new dangers to weather. The performances are generally effective and help add to the atmosphere of dread building around them.