Further notes

MUSICAL BIOHAZARD ~ Voice of Gaia ~ is set in an unspecified year where the threat of bioterrorism has continued to increase in extremity. Much of the story is set in and around the walled Croatian city of Dubrovnik, on the Adriatic seacoast, which faces attack from "Them", zombies infected by an ancient virus. The survivors in Dubrovnik are protected by both their wall and by music, as melodies are known to calm Them, surprising their violent urges.

Lisa Martin (Reon Yuzuki) is a US agent who has been sent into Dalmatia to investigate the viral outbreak for any signs of terrorism. A gathering team sent out to collect food returns after suffering heavy casualties. When they report on a girl on a nearby island who is apparently immune to the virus, Dr. Dan Gibson proposes they head off with Zelg (Makoto Arikawa) and Lovro (Soichi Hirama) to the island and procure the girl in order to create a vaccine. Lisa reports the situation to the US Air Force, who provide a team led by Colonel Maurice Green (Yoshino Keigo) to assist in the mission from Italy's Aviano Air Base. They meet on the USS Wyoming. As the group departs, the citizens of Dubrovnik hold a music festival fronted by Roberto (Shigehito Naoto/Murai Kaiho) in the hopes of distracting Them in time for a vaccine to be developed.

Out at sea, Lisa discovers from Joe, an American doctor based at the air base, that the virus is ancient and is suspected of being in some way involved in the extinction of the dinosaurs. Bernard Chavez's daughter Dilma is soon revealed to be infected. While Dr. Dan Gibson attempts to formulate a vaccine, Lisa discovers that whales are naturally resistant to the virus and obtains a blood sample from one by luring it with the Wyoming crew's singing.