Change the Serie property to be a link:
Serie: "[[The Secret of a Swordfish]]"
This will give you a note for overall information on the series, and a connection point for the graph to link together all the different comics.
For anything to show up in the graph view it needs to be either a link or a tag, and in this case I would definite go for a link. You need to write a lot of information on that note, but just having it there allows for the graph to link the notes.