The important revelations at the end of this episode come from Act 6 of the manga, as does the way Sailor Moon uses the Moonlight Stick in this episode. Similar revelations were saved until Episode 35 in the anime, after the Moon Princess appeared, although the Sailor Soldiers learned about the Dark Kingdom earlier than that. Also, the battle in this episode, where the other Guardians faint, is similar to the battle with Zoisite in Act 7 of the manga, although the resolution was very different - at the end of that manga chapter, Sailor Venus appeared for the first time.

Although it doesn't seem that way when watching it, this is actually one of the most fillerish episodes so far. Strange considering how vital it is to the series! Relatively little manga material was used as the basis for this episode. All the stuff related to Usagi running away from home, the story of Princess Kaguya, and Zoisite's musical monster is original to PGSM. The cliffhanger at the end is also original to PGSM (of course). However, it is worth noting that the story of Princess Kaguya, a famous Japanese story, was an important aspect of the manga sidestory Princess Kaguya's Lover, and the anime movie based on it, Sailor Moon S: The Movie.

Usagi arguing with her mother is something that happened quite frequently in the anime, but nowhere near as often in the manga - mainly because we hardly ever got to see Usagi's mother in the manga. However, the big argument from Act 1 of the manga and Episode 1 of the anime was removed in PGSM, so having some sort of argument between the two of them seems long overdue in a sense.

Finally, it's probably worth pointing out that in the manga and anime, Queen Beryl never appeared in Tokyo.