Teens camping in a northern California retreat are terrorized by mutant insects created by evil, polluting pot farmers.

A toy maker's creations display some very human -- and deadly -- tendencies.

FBI agent Max Reed witnesses Dr. Tetsu Segawa - a researcher for the mysterious Chronos Corporation - being murdered. Dr. Segawa had stolen an alien device known as "The Guyver" from Chronos. College student Sean Barker, whose girlfriend's father was Dr. Segawa, finds the Guyver's hiding spot while watching the forensic team investigating the crime scene.

Once again tampering with mother nature to disastrous results, Dr. Herbert West continues his research while serving time in a maximum security prison for his previous exploits. West's limited prison-cell experiments are suddenly interrupted by the arrival of a new prison doctor and the brother of the girl who suffered from West's experiments 13 years earlier.