Episode 40

For every sadistic psychopath...there were signs. Charm. Narcissism. Lack of empathy. Impulsiveness. Manipulation. Deception. These traits and others are the telltale Signs of a Psychopath. This harrowing half-hour archive series revisits some of the most brutal killers in modern history, reviewing news footage and the words of the killers themselves to see which terrifying traits each killer exhibited. What are the signs...of evil?

American Ninja Warrior is an action-packed series that follows competitors as they tackle a series of challenging obstacle courses in both qualifying and finals rounds across the country. Those that successfully complete a course in their designated region move on to the national finals round in Las Vegas, where they face a stunning four-stage course modeled after the famed Mt. Midoriyama in Japan.

Four longtime friends take dares to outrageous new levels in truTV's hilarious series Impractical Jokers. Q, Murr, Joe and Sal bravely face some of the most unbelievably awkward and brazen hijinks yet, daring each other with over-the-top challenges that are guaranteed to set a new side-splitting standard.

NCIS (Naval Criminal Investigative Service) is more than just an action drama. With liberal doses of humor, it's a show that focuses on the sometimes complex and always amusing dynamics of a team forced to work together in high-stress situations. Leroy Jethro Gibbs, a former Marine gunnery sergeant, whose skills as an investigator are unmatched, leads this troupe of colorful personalities. Rounding out the team are Anthony DiNozzo, an ex-homicide detective whose instincts in the field are unparalleled and whose quick wit and humorous take on life make him a team favorite; the youthful and energetic forensic specialist Abby Sciuto, a talented scientist whose sharp mind matches her Goth style and eclectic tastes; Caitlin Todd, an ex-Secret Service Agent; and Timothy McGee, an MIT graduate whose brilliance with computers far overshadows his insecurities in the field; Assisting the team is medical examiner Dr. Donald "Ducky" Mallard, who knows it all because he's seen it all, and he's not afraid to let you know. From murder and espionage to terrorism and stolen submarines, these special agents travel the globe to investigate all crimes with Navy or Marine Corps ties.

No job is more stressful, dangerous or exhilarating than those of the Firefighters, Rescue Squad and Paramedics of Chicago Firehouse 51. These are the courageous men and women who forge headfirst into danger when everyone else is running the other way and whose actions make the difference between life and death. These are their stories.