These CW superhero shows are pretty hit and miss, with some being sporadically great (the Flash, which has what the kids call "heart") to usually crappy (Legends of Tomorrow). They seem to be making enough cash though, because the CW keeps rolling them out, with Supergirl and Black Lightning as the newest additions to the super lineup. Arrow has always existed a bit in the middle, darker than Flash, but not as campy or bright as Supergirl.
For the uninitiated, Green Arrow is basically DC's Hawkeye, and a little like Batman with a bow and arrow. After a violent shipwreck at sea, billionaire playboy Oliver Queen was presumed dead. Really, he was cooling out on a remote island in the South China Sea for 5 years. Oliver eventually returned home to Starling City, and kind of decides to be a superhero, and a broody one at that. He becomes the Arrow and allies himself with former soldier John Diggle, computer-science expert Felicity Smoak, lawyer-turned-vigilante Laurel Lance, billionaire inventor Ray Palmer (who eventually becomes the Atom), and his sister Thea Queen. Then he starts blasting everyone with arrows and stopping criminals. It's a pretty straightforward origin.
In the last season, he's eventually forced to admit that he's Arrow, and he gets sent to jail, just like (deep breath) Batman, Daredevil, Hawkeye, Punisher, Luke Cage, Spider-Man and Ant-Man. So, yeah... a pretty unique plot-point to say the least. Now, a new Green Arrow is on the streets, shooting everyone, and Oliver needs to figure out how the hell he's going to get home and kick this guy's ass, or at least challenge him to an arrow competition.
The trailer is below, and you can see for yourself what prison is like on the CW. Here's a hint: there aren't many shanks and the showers are pretty safe.
Arrow season 7 premiers October 15.