Congratulations!
As mentioned in the puzzle itself, this is PART ONE of a set of four puzzles. It is based on the story of the Night ∞ Series, a set of four Vocaloid songs (and associated music videos). In it, several actors repeatedly act out the same play, which goes horribly wrong each time. (Link to videos)
Knowledge of the series might make the theming and puns a bit more enjoyable (and easier to get), but you do not need to know anything about it to solve the later puzzles. Feel free to skip it if you’d like! Or you can read the summary here and the plot descriptions linked on each page, if you want a quick overview.
[Content warning: as suggested by the first puzzle, the remainder of the songs have the same sort of “dark” tone. The videos use a “paper doll”-like art style, and no violent content is shown. The story is abstract/confusing enough that it will likely not have a harmful effect on any solvers. But I figured it was better to warn people just in case.]
[Additionally, there are a few slightly crude references in the upcoming puzzles. Solve at your own discretion.]
As before, feel free to contact me for hints or feedback - always happy to hear from people solving my puzzles. Enjoy!