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.

Sean Barker became the unwilling host to an alien bio-armor known as the Guyver. A year ago he destroyed the Kronos Corporation, an organization of mutants who want the Guyver. Now he is trying to find why the Guyver unit forces him to fight and kill evil.

One night, high school student Sho Fukamachi discovers a mysterious metal object. Then in a blinding flash of light, Sho finds that he has accidentally fused with the Guyver, a mecha of mysterious alien design. Now, to save his girlfriend, Mizuki Segawa, along with the entire world, Sho must become the Guyver to fight the Chronos Corporation and their biocreatures, called Zoanoids, who are hell-bent on world domination.

Roxanne, Julie, and Alex are THE SUITS, martial artists granted extraordinary powers with dark side effects. The trio must reunite and overcome their own challenges to defeat a new threat to mankind.