: As rig boss Magnus MacMillan loses control of the increasingly paranoid crew, Rose takes a more prominent leadership role.
: Geologist Rose Mason deduces that the mysterious ash and spores found on the rig belong to "the Ancestor," which she identifies as the oldest organism on Earth. : As rig boss Magnus MacMillan loses control
: While investigating pressure malfunctions on the seabed, the crew discovers a strange symbol consisting of concentric circles. : As rig boss Magnus MacMillan loses control
: Baz and Garrow attempt to shut down the rig's pipes completely while exploring the pump control room. : As rig boss Magnus MacMillan loses control
: Fulmer, who has been exposed to the Ancestor, struggles to maintain his sanity. Baz believes Fulmer is the only one who can help stop the unfolding disaster due to his connection to the entity.