When Brian helps Agents Harris and Boyle investigate the murder of a retired FBI agent, they’re shocked to find a link to the elusive head of a notorious drug cartel. Also, Brian reconnects with an old flame, Shauna but worries her renewed interest is really in the NZT version of him.

When an assassin makes an attempt on Senator Edward Morra's life, Brian is ordered to sabotage the FBI's investigation into it in order to prevent exposing the Senator's connection to NZT. As Brian and Morra's fates become further intertwined, Brian is faced with how far he's willing to go to protect the politician.

When Brian’s closest relationships implode due to his inability to cut ties with Eddie Morra, he goes rogue from the FBI to free himself from the senator’s control. In Russia, he searches for Piper, Morra’s former associate turned adversary, and her alternative NZT vaccine. Also, Rebecca comes closer to discovering Brian’s connection to NZT and Senator Morra.