FBI Special Agent Don Eppes (Rob Morrow) recruits his mathematical genius brother Charlie (David Krumholtz) 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. Assisting Don at the FBI is his partner, Terry Lake (Sabrina Lloyd), and new recruit David Sinclair (Alimi Ballard). Dr. Larry Fleinhardt (Peter MacNicol) is Charlie's friend and colleague who urges Charlie to focus more on his university studies than on FBI business. Don and Charlie's father, Alan Eppes (Judd Hirsch), is pleased to see his two sons working together, but fears their competitive nature will lead to trouble.