A special agent working out of FBI's Philadelphia office, Lea Marquez was working undercover in an underground strip club when she encountered Zach Slater. Lea had been tracking a money laundering operation, and at least one of the accounts in question had been tied to Zach's casino. Zach, however, had infiltrated the underground club in his efforts to help Jesse and Angie Hubbard find their missing daughter, Cassandra, who had been kidnapped by the Russian mob.
Although Zach was a suspect, Lea believed that he was on the correct side of the law and kept him in police custody with her as she searched for Cassandra. At first, Zach flirted with Lea and teased her about their first encounter while she was undercover at the strip club. As time passed, they became closer and when Zach was accused of the murder of the Russian Uri Koslov, Lea was certain that he had been framed. They continued to work together and found proof of Zach's innocence. Lea and Zach celebrated by giving in to their attraction to one another but pulled back before things went too far.
While Lea wondered if Zach was truly over his ex-wife, Zach was angered that Lea had hid her suspicions that Jesse had framed him for Uri's murder. Zach defended his friend and explained that Jesse had no choice but to frame Zach in order to save his daughter. They both agreed that it was for the best that they did not pursue a relationship since they did not have trust between them. Later, Lea arranged for the charges against Jesse to be dropped and apologized to Zach. He accepted her apology and they agreed that there was something between them and shared another kiss.