Episode 4

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.

In a ruined and toxic future, thousands live in a giant silo deep underground. After its sheriff breaks a cardinal rule and residents die mysteriously, engineer Juliette starts to uncover shocking secrets and the truth about the silo.

FBI is a fast-paced drama about the inner workings of the New York Field Office of the Federal Bureau of Investigation. These first-class agents, including Special Agent Maggie Bell and her partner, Special Agent Omar Adom 'OA' Zidan, bring all their talents, intellect and technical expertise on major cases in order to keep New York and the country safe.

Tracker features lone-wolf survivalist Colter Shaw, who roams the country as a "reward seeker," using his expert tracking skills to help private citizens and law enforcement to solve all manner of mysteries while contending with his own fractured family.

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.