In RPG Maker, you have a party of actors.
You can add actors to the party, or remove actors from the party at anytime. However, by default, all of the actors in the party can be interacted with in the menu, and may participate in battle.
There may be situations where you just want an actor to “appear” as if they are part of the the party, but aren’t actually in the party. For example, let’s say an NPC asked you to accompany them through a cave, and you wanted the player to see that the NPC is following them, but you didn’t want them to actually use the NPC in battle.
With this plugin, you can add actors as “guests”, which would simply allow them to show up as non-party followers.