The film opens with a robbery gone wrong and one of the men disappearing except for his clothes and a case full of money.
The film turns into a nifty film noir for a while a detectives try and solve the case of the missing gangster. They question his girlfriend, a very attractive woman who sings in a nightclub, but to no avail. Soon a few more disappearances happen and the police are stumped.
A young scientist comes to aid the police with a strange theory about men who have dissolved as a result of the H bomb tests and have become a new form of life. The police scoff at this until they actually see the green monster for themselves. It attacks the nightclub and dissolves several people including a dancing girl and a cop.
The dissolving scenes are handled very well and the mixture of film noir and sci-fi are beautifully blended. The best scenes are when a man recounts the tale of when he discovered the H Men on a deserted ship. The mood, the photography and the creepy music make this a few moments of film I will never forget.
Good stuff here as Sony turned this out on their "Icons Of Sci-Fi" set along with "Mothra" and "Battle In Outer Space". Highly Recommened!!