Dedicated FBI agent Don Eppes (Rob Morrow) couldn't be more different from his younger brother, Charlie Eppes (David Krumholtz), a brilliant mathematician who, since he was little, has yearned to impress his big brother. Don has recruited Charlie, a mathematical genius, to help the Bureau solve a wide range of challenging crimes in Los Angeles. The two brothers take on the most confounding criminal cases from a very distinctive perspective. Don is joined on his team by fellow agents Megan Reeves (Diane Farr), a behavioral specialist who brings psychological insight to the investigations; David Sinclair (Alimi Ballard), a streetwise survivor who grew up in the Bronx; and ex-military man Colby Granger (Dylan Bruno). After initial reluctance, Don's team has welcomed Charlie's innovative approach to crime solving. Alan Eppes (Judd Hirsch) is happy to see his sons working together, even though he doesn't understand the intricacies of what Charlie does for a living. It is Charlie's colleagues at CalSci who further refine his approach and help him stay focused. Physicist friend Dr. Larry Fleinhardt (Peter MacNicol) constantly challenges Charlie to employ a broader point of view to his work with the FBI, and Amita Ramanjuan (Navi Rawat), Charlie's former grad student, frequently helps him see cases in a new light. Season 4 brings Don and Charlie together on perplexing cases ranging from a mass poisoning at a cult compound to a death connected to the secret world of reality games. This five-disc, 18-episode set contains all the compelling cases from the 2007-8 season.