(Capcom's primary storyline)
The Seabed Laboratory was a Neo Umbrella facility based in the ocean around the Chinese coastline, with an oil rig serving as the surface façade. The facility, itself was designed for the Haos development project, being based around a divergent plate boundary, where extremophiles could be extracted for further use in B.O.W. development.
After learning the coordinates of the facility's location, Chris Redfield and Piers Nivans infiltrated the facility, which was heavily guarded by Neo-J'avo. They eventually found the Haos incubator, from which the giant B.O.W. emerged. Chris and Piers evaded the Haos, but the creature eventually caught up with them, destroying Piers' arm and attempting to crush Chris in its grasp. However, Piers infected himself with the Enhanced C-Virus which mutated his arm. Piers then attacked the Haos, forcing him to let Chris go, and the two then proceeded to fight the hulking beast. The two BSAA agents seemingly defeated the B.O.W. and proceeded to evacuate the facility.
Meanwhile, Jake Muller and Sherry Birkin, who had once again been captured by Neo Umbrella, managed to escape their cell and attempted to escape. They eventually found the power source of the facility: a giant energy production plant which used the underwater volcanos' power to supply energy to the facility. As they advanced, Ustanak appeared and tried to finish Jake and Sherry once and for all. After a prolonged battle, Ustanak was defeated, but the battle had greatly damaged the power plant, and the facility started to fall apart. Jake and Sherry successfully evacuated the location.
Elsewhere, as the BSAA agents rushed to escape the facility, Piers' condition got worse. Realizing that he would soon lose his sanity, he pushed Chris into an escape pod and let himself die as the facility exploded, taking him and the Haos with it.