Set in 2005, between the events of Resident Evil 4 and Resident Evil 5, Revelations depicts the Bioterrorism Security Assessment Alliance (BSAA), a counter-terrorism group which Chris and Jill have co-founded, shortly after its establishment. The game begins as the latter and her partner, Parker Luciani, board the Queen Zenobia.
Set mainly in Europe, Revelations sees the player characters through ravaged cities, ports, and snowy mountains. Jill and Parker are sent out by BSAA head Clive R. O'Brian to search for Chris and his new partner, Jessica Sherawat, who have reportedly gone missing during a mission. Meanwhile, Chris and Jessica are operating in a snowy mountain region, searching for evidence of the return of Il Veltro, a bio-terrorist organization responsible for the attack and subsequent outbreak in Terragrigia, an artificial aquapolis that was utterly destroyed on orders from Morgan Lansdale, director of the Federal Bioterrorism Commission.
Jill and Parker find their way into the Mediterranean Sea, acting on Chris' last known coordinates. They find themselves taking a tugboat to a seemingly abandoned cruise ship known as the Queen Zenobia. On board, they find horrific mutants known as Ooze, victims of the t-Abyss virus, and are unable to locate Chris or Jessica. Instead, they find a dummy of Chris and are knocked unconscious by an Il Veltro agent, stripped of their weapons, and separated.
Chris and Jessica, meanwhile, find a base of operations for Il Veltro; an airstrip in the mountains. Being informed by O'Brian that Jill and Parker are missing in the Mediterranean, they are then sent out to investigate their whereabouts. Meanwhile, the pair of Keith Lumley and Quint Cetcham are dispatched to the airstrip to find out more about Il Veltro's actions. Back on the Queen Zenobia Jill wakes up in one of the cabins and is contacted by Parker who says he woke up on the other side of the ship and to regroup on the bridge. After meeting up they are attacked by an FBC agent named Raymond Vester who knows Parker from when he was an FBC agent. Meanwhile at the airstrip Quint and Keith find video footage of an invisible creature killing a Veltro operative. Which is later revealed to be a new form of Hunter which has been infected with the t-Abyss which allows it to turn invisible for sneak attacks. Meanwhile Chris and Jessica land on a ship thinking its the Queen Zenobia but discover that they are on the Queen Zenobia's twin the Queen Semiramis. On the Zenobia Jill and Parker are desperately trying to escape the flooding engine room which after they escape they head to the Comm tower to try and contact O'Brian to report whats really going on. But are met with bad news that the Regia Solis, the satellite used to fry Terragrigia using the sun's power, has been reactivated and is being aimed at the Queen Zenobia. Luckily, Quint leads Jill and Parker (via comm link) to the UAV (one of the three used in the Terragrigia attacks to spread the virus) on the ship's bow, and the two race against time to find the controls. with the controls, Jill and Parker use the UAV's chaff to guide the Satellite's targeting system away from the ship. However, as the Regia Solis hits the UAV, a wave hits the ship, and threatens to sink the Queen Zenobia.