“The Last Ship,” TNT’s post-apocalyptic drama about a crew of plague survivors trying steadfastly to save humanity, continues to add heavy action to a season already tight with tension.

In Episode 11 of Season 2, titled “Valkyrie,” Sean Ramsey (Brían F. O'Byrne ) will send forth a message that ties the Navy to a massive disaster.

As reported by Spoilers Guide, Chandler (Eric Dane) will attempt to infiltrate their network. In the course of the episode the Nathan James will locate the source of a signal coming from "The Immunes." This turns out to be a mysterious oil platform somewhere out in the middle of the ocean. When the crew gets to the source, Chandler and his team will engage in battle with civilian forces that have sided with the Ramseys' scheme.

A promo of the upcoming episode has Sean Ramsey, the leader of "The Immunes," staring right at the screen and saying, “To the captain of the USS Nathan James, we are coming for you.”

Judging from the scenarios being teased for this episode, show creator Hank Steinberg wasn’t kidding around when he hinted back at Comic-Con that “The Immunes” would be playing a darker role in the coming shows.

“What if somebody didn’t want the cure? Who would that be?” Steinberg proposed.

As reported by Entertainment Weekly, he wondered aloud: “Wouldn’t there be people who were naturally immune to this disease and if they were, they would become almost like superheroes in this world. Everyone else is scrambling around with gas masks and scarves…but they can walk the earth untouched. They can break in anywhere, take anything they want, and if they band together, they can become incredibly powerful.”

The notion that "The Immunes" are pulling the country apart, Steinberg said, would be an idea explored in the second season.

“The Last Ship” airs Episode 11 of season 2 on Sunday, Aug. 23 on TNT.

Watch next episode's trailer here: