S1, E1: In the series premiere, Don races to capture a serial rapist who has begun to murder his victims. Charlie is recruited by Don to help track the killer. He creates a mathematical equation to identify the killer's point of origin by working back from the crime scene locations. Charlie's obsession with the case leads him to seek the insight of his colleague, physicist Dr. Larry Fleinhardt. Meanwhile, their father, Alan, is pleased to see his sons working together but fears their competitive nature will lead to trouble.