A narcotic theft during a rainstorm gets interrupted when one of the guys, who is out in the rain, starts screaming before he makes it to the escape car. The driver takes off, afraid of what happened to him. Something came from the sewers and basically dissolved the poor guy, as the only thing left on the street are his clothes. The police investigate this strange appearance and question the guy's wife, who works at a night club, but she doesn't know anything. The police, however, get help from a scientist, who thinks this may have to do with H-bomb tests in the Pacific, especially when a ghost ship appears in the harbor. Then, there's a flashback to some fisherman who had discovered that ship out on the sea. They find nothing but piles of clothes until an "H-Man" makes an appearance. At first the creature is like a blob and once it attaches to someone starts melting them. Then, it starts glowing and takes on a vaguely humanoid shape. In the last part of the movie the action takes place down in the sewers beneath the city and they try to destroy the radioactive creatures with fire.
THE H-MAN is just like a giant monster movie only the monsters are--and puddle--sized. The film is definitely worth checking out, as there are some impressive special effects for the time period in which the movie was made, with all these people dissolving