is a reference to influential autodidactic Indian mathematician Srinivasa Ramanujan. (seasons 2–6, main; 1, recurring) Megan Reeves (Diane Farr) is an FBI behavioral specialist. She was involved romantically with Larry Fleinhardt and left the FBI to counsel troubled young women. (seasons 2–4) Colby Granger (Dylan Bruno) is an FBI field agent. Once thought to have betrayed his colleagues, he is now back in their good graces and confidence. (seasons 3–6, main; 2, recurring) Liz Warner (Aya Sumika) is an FBI agent, formerly involved with Agent Eppes. (seasons 5–6, main; 3–4, recurring) Nikki Betancourt (Sophina Brown) is an FBI agent with four years' experience in the LAPD and a law degree. (seasons 5–6) Temporary characters on the show were often named after famous mathematicians. For example, in the episode "In Plain Sight" (season two, episode eight), one of the criminals is named Rolle and Charlie's father mentions a meeting with a man named Robert Peterson. Episodes Opening: (Voice-over by David Krumholtz) We all use math every day. To predict weather, to tell time, to handle money. Math is more than formulas and equations. It's logic; it's rationality. It's using your mind to solve the biggest mysteries we know. Season 1 (2005) The first season aired between January 23, 2005, and May 13, 2005, at 10:00 pm on Fridays. It started the working relationship between Los Angeles' FBI field office and Charlie Eppes. The main FBI agents are Charlie's brother, Don Eppes, and Terry Lake, as well as David Sinclair. Don and Charlie's father, Alan Eppes, provides emotional support for the pair, while Professor Larry Fleinhardt and doctoral student Amita Ramanujan provide mathematical support and insights to Charlie. Season one was a half-season, producing only 13 episodes. Sabrina Lloyd played Terry Lake, an agent, in this season; she was later replaced by Diane Farr, who played Megan Reeves. Season 2 (2005–06) The second season aired between September 23, 2005, and May 19, 2006, again at 10:00 pm on Fridays. Season two has several changes to Don's FBI team: Terry Lake is reassigned to Washington and two new members join Don and David Sinclair: Megan Reeves and Colby Granger. Charlie is challenged on one of his long-standing mathematical workpieces and starts work on a new theory, cognitive emergence theory. Larry sells his home and assumes a nomadic lifestyle while he becomes romantically involved with Megan. Amita receives an offer for an assistant professor