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Invisible Scarlet O'Neil, created by Russell Stamm, was one of the first female superheroes, if not the very first. As her name suggests, she had the power to turn herself invisible, and she used this power to help her solve crimes. In the early days, the invisibility gimmick was quite prominent, and a small panel explaining it could be seen at the beginning of each strip (as seen here). However, over time it mattered less and was used less, and eventually the strip was renamed "Scarlet O'Neil". Perhaps she was so competent at bagging criminals normally that she no longer needed invisibility powers. Or perhaps super powered heroes and heroines had just gone out of style by that point. Or perhaps both.
Action and adventure strips such as this tend not to have Christmas related strips, but we have one here. The bad guys have utilized a community Christmas tree to send signals to each other, which Scarlet just happens to notice while sitting on a park bench. This would seem like a fairly normal thing to do, if it weren't for the fact that she's invisible while doing it, which it doesn't seem like she should need to be. But, I guess sometimes you just want to get away and enjoy some Christmas lights on your own without being bothered, which I can fully understand.
I'm not sure who these bad guys are supposed to be. The use of "comrade" suggests Soviets, but the name "Iltz" doesn't sound Russian, so maybe they're Nazis. I guess really they're just generic European-esque baddies.