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.

Limitless, based on Relativity's 2011 Bradley Cooper thriller, picks up where the movie left off and follows Brian Sinclair as he discovers the power of the mysterious drug NZT, and is coerced into using his newfound drug-enhanced abilities to solve weekly cases for the FBI.