Zhang and his daughter, Suyin, an oceanographer, are supervising a mission to explore what may be an even deeper section of the Marianas trench concealed by a cloud of hydrogen sulfide, forming a thermocline. The mission is being conducted by Lori – Taylor’s ex-wife, Toshi, and The Wall in a submersible. The mission appears to be going well until a very large creature hits the submersible and causes it to lose contact with Mana One.