North Atlantic, 5 months ago: A British submarine has been infected by the pandemic, and all but two crew members have died.

Life is returning to normal on the Nathan James. A crew member alerts the Commander and Dr Scott to the possibility that a USN hospital ship headed out to sea with the missing lab equipment from Norfolk. They decide to change course to find the USS Solace. 

Danny introduces two new recruits to his team --  Special Chief "Wolf" Taylor from the Australian navy, and Lt Ravit Bavis from Israeli Defense Forces.

The Nathan James is having trouble contacting the Solace. 

The special forces team works out in preparation to board the Solace. Tex fills Burk in on Lt Bavis.

Comms has picked up on the Solace's beacon, but it's not responding to hails. The senior officers and Dr. Scott go over blueprints of the ship. 

The NSU gears up to board the Solace. 

Chandler and the NSU board the team, but no one is aboard. They lose contact with the Nathan James once they are inside the ship. Chandler's team finds an iPad playing a video and a cup of coffee, and Tex's team finds the body of man who has recently been shot. They then find the crew, executed in the kitchen. Chandler's team finds a team of doctors performing surgery, and are informed that "they" are still on the ship. 

The two teams are unable to comminucate with each other due to radio interference, but the message about hostiles onboard gets through to the Nathan James, which prepares for an attack. Tex's team moves to secure the lab, and Chandler's team attempts to flush out the pirates. 

Foster assigns a crew member to do a sonar search of the area.

Chandler's team comes under fire, and the determine that the attackers are military. Wolf and Miller find a group of the hostiles, and take them out.

Tex's team finds the hostiles raiding the lab, and Bavis walks in disguised in a lab coat and then shoots the men. The lab has been destroyed. 

The men from the British submarine make a taunting threat over the PA.

The leader of the Solace crew tells Chandler how to get the doctors and other crew off the boat. The NSU onboard continues to go after the hostiles, and the Nathan James assists the fight by training its guns on the Solace. 

Burk takes a bullet for Bavis in his vest, and they discover that the hostiles rigged the ship to blow.

Chandlers team unloads the 

A possible submarine comes up on the sonar.

 Bavis attempts to duffuse the bomb. It seems she has it, but then she discovers a second wire. 

Chandlers team is unloading the doctors to the pilot boats when they come under fire. Wolf is shot in the thigh, and the leader of the Solace crew is fatally hit in the neck.

Bavis and Burk work together to diffuse the second bomb which is attached to a giant oxygen tank. 

A Spanish man is hit by a shooter off the deck of the Nathan James.

Tex manages to get the bomb off the oxygen tank. Chandler gets the drop on the British officer, who threatens to blow up the ship, but Tex has thrown the bomb over the railing and it explodes midair. In the confusion, the British man jumps overboard. Chandler shoots at him, but misses. The man disappears into the ocean.

The officers think that the hostiles are mercenaries, and continue to hunt for the submarine they were likely based on.

The head doctor from the Solace requests to stay with the Nathan James. 

Jeter tells Chandler that the injured hostile they captured was speaking Spanish.

Sorensen and Declan head out to meet "the boss." Declan is tied to the hostiles that attacked the Solace. A submarine rises to meet the small tinder boat they are on.