The evil criminal leader Kendrick has kidnapped an elderly biochemist who holds the secret to creating a biological superweapon. The only person who can possibly stop Kendrick and his gang is L. A. cop Sam Kettle and martial arts master Jun Kim (uncle of a little girl also kidnapped by Kendrick). Together, they go to war against an army of ninjas to rescue the hostages and bring their kidnappers to justice.

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.