LOS ANGELES, Sept 25 — The NBC series “Heroes,” which aired from 2006-2010, was about a group of characters who slowly come to the realisation that they have superpowers. A ratings hit in its first season, the show became increasingly complicated and soon lost its lustre. Five years later, the network is premiering a sequel series, titled “Heroes Reborn.”

While it’s possible to watch the series without having ever seen any episodes from its forerunner, “Heroes Reborn” assumes that viewers have some familiarity with a number of characters and concepts. Get up to speed by reading this before watching the show’s premiere:

Noah Bennet (aka: “HRG,” for “Horned-Rim Glasses”) — Bennet is a normal (ie: non-superpowered) human, and father of Claire Bennet, a teenager with regenerative powers. Bennet’s primary allegiance has always been to his daughter, though he’s also an agent of “The Company,” a shadowy organisation whose various members and leaders have tried to suppress, study and/or protect superpowered humans (sometimes all three). Bennet is, as his nickname implies, a square, but he is quite good at tasering people. When we first met Bennet in season one, he only cared about making sure Claire hid her special abilities. But at the end of season four, Noah watched apprehensively as Claire publicly outed herself by using her powers on TV.

Mohinder Suresh — Mohinder is a genetics professor who is introduced in season one as the dutiful son of author and geneticist Chandra Suresh. After Chandra is murdered, Mohinder uses his father’s research to develop a synthetic serum that will give superpowers to normal people. It doesn’t go well. Mohinder goes a little crazy after he develops spider/insect-type powers, including the ability to climb walls and make weblike cocoons. (He eventually loses all his powers except for superhuman strength.) Instead of joining his allies to stop evil circus ringmaster Samuel in season four, Mohinder returns to Madras so he can make up with his jilted lover.

The Haitian — Everybody likes The Haitian because he doesn’t have any backstory beyond an evil sibling. In fact, The Haitian didn’t even have a first name until season three (he’s thereafter known, though infrequently referred to as “René”). He doesn’t say much, and can often be seen wiping out heroes’ memories and powers. He’s very good at his job.

Hiro Nakamura — Hiro is an unfailing optimist and giddy nerd who discovers that he has teleportation and time-travel powers. In season four, Hiro develops a brain tumour (later removed) that forces him to limit the use of his powers.

Matt Parkman — Matt is a telepathic cop who uses his powers to manipulate people’s memories and their perception of reality.

Molly Walker — Molly is a child who was orphaned by Sylar, and then taken in by The Company in season one. She’s later adopted by Mohinder and police officer/fellow hero Matt Parkman. She is considered an asset to both The Company and to the heroes because she can locate other superpowered individuals. (She’s basically a human version of “Cerebro,” the machine that can locate mutants in the X-Men comics.) Molly hasn’t been involved in the heroes’ stories since season two, presumably because they figured out that endangering a child’s life is a bad idea. Might she be the “Molly” played by actress Francesca Eastwood in the new series? — The New York Times