How does magic play an essential role in Chapter 4: The Abduction?

The events take place because Holly is low on magic and needs to replenish it through the Ritual. Her lack of magic also makes it possible for Artemis and Butler to capture her, because she can't fight back with magic against them. Artemis and Butler, on the other hand, are able to capture Holly because they now have knowledge of the fairies' magic and are able to combat it. They wear sunglasses to prevent Holly from doing a mesmer spell on them, for example. Their knowledge of fairy secrets puts Holly off balance, just as it will do to the other fairies that Artemis will encounter in the future.