The hero "Nightshade" could be an amalgamation of two different Justice Society members who costarred with Jay Garrick/The Flash in the 1940s comic books. Dr. Midnite, a surgeon by day and vigilante by night, who fights crimes despite only being able to see in complete darkness. Midnite uses a variety of non-lethal weaponry like blackout bombs which knock out all light. He has an owl as a sidekick named "Hooty". The other character is The Sandman, not to be confused with the Neil Gaiman character of the same name. Wesley Dodds was the first iteration of The Sandman, who would receive dreams telling him of someone in need of help. With his sidekick Sandy, he would don a fedora and gas mask and use his non lethal gas gun to attempt to right wrongs. The character of Nightshade is a Doctor like Dr. Midnite while sharing a similar outfit to that of The Sandman. Also, given the time frame, the 1950s, while in the Silver Age of Comics would quite possibly be the Golden Age of this particular iteration of the Flash.
Amanda Pays' husband Corbin Bernsen was initially cast as the Ghost but had to drop out because of scheduling conflicts with L.A. Law (1986).
"Do not adjust your set, I control the horizontal, I control the vertical." Is an in-joke to the popular 60s sci-fi show The Outer Limits (1963). In-universe, "The Ghost," being from 1955, would not be aware of it.
This episode takes place in 1955 and 1990.
There was a major blackout in Central City in 1971.