The crew of Nathan James discovers that hospital ship USNS Solace was sent to sea to wait for Dr. Scott's cure. Captain Chandler sees an opportunity to add another ship to their fleet while Rachel is eager to find a lab better equipped to replicate the vaccine. When Solace fails to respond to radio communications, Chandler and his team board the ship..and come face-to-face with an unexpected enemy.

Chandler tracks the immunes to Northern Florida; Rachel comes across a secret formula that her mentor was working on; Chandler's team locates an immune compound.