A frustrated Boston detective searches for the maniac responsible for mutilating a number of university coeds.

People are dying mysteriously and gruesomely, and nobody has a clue what the cause is. Only health worker Mike Brady has a possible solution, but his theory of killer slugs is laughed at by the authorities. Only when the body count begins to rise and a slug expert from England begins snooping around does it begin to look like Mike had ...

An experimental submarine with a very experienced crew, the "Siren II" is sent to find out what happened to the "Siren I" after it mysteriously disappeared in a submarine rift. Things go awry when they begin to find things that shouldn't be there...

Like in the novel of Jules Verne four persons try to get to the centre of the world by entering into a world of caves by a volcano. On their way they discover among other things also prehistoric animals like some dinosaurs,