Quest Handling System consists of a runtime system and editor tools made in c++ and accessible in both blueprints and c++.
Quest Editor let's you create very complex quests in a simple way, by combining nodes into a graph similarly to a blueprint graph editor (it's not a blueprint graph).
There are several quest nodes already in the plugin, which govern the flow of a quest or make up objectives, but if you need some custom behavior you can easily create your own quest nodes that add new functionality or integrate other plugins.
Runtime quest debugging makes debugging more streamlined by displaying useful information without having to go through a log.
Serializattion (Saving/Loading) is already handled and can be easily integrated into your own saves.
You can create quest nodes either in blueprints or c++. A small part of node functionality can only be accessed in c++.