When a team called Hermes goes missing after a failed mission in the Arctic Ocean, the Orpheus team is sent down there to see what there is to salvage. Raymond, a specialist in extractions, joins, they have an unexpected turn of events when they are in danger of dying just like Hermes.
When the Orpheus find the ship above them, they find themselves in the middle of what could possibly be radiation that killed the entire crew above them. When survivors are found, they are not at all happy to find strangers aboard their ship and Clem makes a discovery that gives him hope.
With eminent danger as a possibility, the Orpheus crew must draw sticks as to who is going to be the martyr and go into a volatile Reactor Core to cool it down on Volos, the Russian submarine. On a mission to retrieve a motherboard from Hermes, Clem thinks he sees a familiar face, his wife Catherine.
When Catherine is found alive and the discover that Zupov is not dead, they are double-crossed and are forced to leave 3 Orpheus Team members behind as they escape for their lives. Rather then going to the surface, they decide to go deeper and finish what they started. With the mission of collecting a sample, one key member has to make a choice that will change their life or could possibly end it.
With Volos in close range of the Orpheus, the team works hard to find out a way to get out of range. Meanwhile, a surprise is for Raymond when he tries to fire the weapon at the Orpheus. At the same moment, Hatsuto and Lowe get a unexpected visitor from America.