Biohazard Zero takes place in 1998, before the events of the first Biohazard game. During the cinematic opening sequence, the S.T.A.R.S. Bravo team's helicopter is forced to crash-land outside Raccoon City. When the team splits up to investigate, rookie cop Rebecca Chambers seeks shelter from the rain in a dilapidated train. It seems that all the passengers are dead until she comes face to face with an escaped convict named Billy Coen.
When the mangled bodies filling the train start to come to life, an unlikely duo is formed. Rebecca and Billy may not have much in common, but they know they must work together to survive. The two must disembark from the train and explore new locations. Eventually you will learn the secrets of the Raccoon City saga.