This week’s Arrow is called “Unchained” but it very easily could have been titled “Reunion.” Several characters ranging from recurring to series regulars in the past all come back this week, along with a major new villain. They manage to cram a lot into one episode, and are building to something major happening soon.

Team Arrow largely gets distracted from their war with Damian Darhk in “A.W.O.L” Lyla and Diggle go out for a well-deserved night on the town, with some actual normal concerns like getting back in time for the sitter. Of course, that can’t last, and they get interrupted by the sudden appearance of Alan Chang, ARGUS agent. Chang then gets attacked and carried off by unknown assailants who are not Darhk’s Ghosts for once.

Arrow has been doing flashbacks almost every episode. Now, they do things a bit differently. The episode opens with a flash-forward, four months from now. Oliver stands over a fresh grave, looking very upset. Barry, also looking sad, turns up. Oliver vows “to kill him,” the “him” in question presumably being whoever is responsible for the grave. They carefully don’t show us the name on the marker.

The mid-season finale arrives for Arrow in “Dark Waters.” It starts off well enough, following up on Oliver’s project to clean up the harbor. It looks like a huge success, with a lot of people turning out, and some good press coverage for Oliver. Of course, things don’t stay bright and cheery on Arrow for long, so I wasn’t terribly surprised when the event was attacked, although it was a new and different kind of attack, I’ll give them that.