MI-5 (BBC America)

British action-drama MI-5 follows the inner workings of a fictional team of agents within the United Kingdom's real-life Military Intelligence security agency. Section B's covert operatives fight global terrorism on a daily basis, often putting their own lives on the line to ensure that the bad guys are stopped in their tracks. The series often bases its storylines on modern world events; most plots center on the seemingly limitless threats posed by terrorists. On any given day, the agents are called upon to infiltrate extremist groups, befriend or bribe potential informants, intercept weapons of mass destruction, and diffuse explosives. Through it all, these highly trained "spooks" keep cool heads and attempt to out-maneuver their dangerous enemies, all while maintaining their top-secret cover and keeping their families and friends at an emotional distance -- and in the dark about their true identities. Over the series' many seasons, the cast has undergone plenty of changes as agents have been killed or injured on duty or otherwise ousted from the elite group. But the imposing head of the task force, Harry Pearce (Peter Firth), remains, as does a core group of agents that includes Ruth Evershed (Nicola Walker), Adam Carter (Rupert Penry-Jones), and Zafar Younis (Raza Jaffrey).

Fast-paced and smartly written, MI-5 is filled with suspense, action, and unexpected twists and turns that will keep spy fans guessing. But the series' violent nature makes it iffy for tweens and young teens. Gunplay, beatings, stabbings, and bombs are common, and characters are often shown bloodied, in pain, pleading for their lives, and even dying. Sensitive viewers -- especially those personally affected by terrorism or other violence -- may also be disturbed by the idea of the unseen threats posed by covert terrorist groups.

And, of course, there are the often-questionable methods the agents use to get results -- including violence, threats, bribery, and deception. Young viewers may not understand why the so-called "good guys" are able to cross the lines in certain situations that would otherwise call for serious consequences.