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. 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.