Leon S. Kennedy, a U.S. government agent, is dispatched to a war-torn Eastern European country to investigate rumors of Bio-Organic Weapons (B.O.W.s) being used in the civil war. Upon his arrival, Leon disregards orders to be pulled out and decides to stay and uncover the truth behind the B.O.W.s. He soon allies with a mysterious freedom fighter named Alexander 'Buddy' Kozachenko, who has his own vendetta against the oppressing government forces. Their search leads them into the heart of chaos, where they find themselves up against not just the local militia but hordes of deadly creatures created through bio-engineering.

As Leon delves deeper into his investigation, he encounters Ada Wong, a femme fatale with ambiguous motives who appears to be involved in the trafficking of biological weapons. The plot thickens with political maneuvering and treachery, as hidden agendas come to light and the true scale of the B.O.W. crisis is revealed. Faced with formidable enemies and limited time, Leon must navigate through a web of deceit and danger to stop a catastrophic event that threatens to unleash widespread havoc.