This OVA adapts the first four chapters of the Guyver manga. It follows high‑school student Sho Fukamachi, who discovers a mysterious metal object that fuses with him, transforming him into the Guyver. The story covers the genesis of the Guyver, Sho’s battle against the Vamore, the confrontation with Guyver 2, and the introduction of Guyver 3. Key differences from the manga include the omission of Tetsuro, who is replaced by Mizuki, and the replacement of the agent Lisker with a female agent named Valcuria, resulting in a female Guyver 2. The OVA also delves into Sho’s psychological response to his new circumstances, including a stark scene in which his friends are assassinated in cold blood.