Thanks, Michael!! I have to agree with you totally about The Medusa Plot. It's really, really, really good and I can hardly stand waiting for the next one. There is a lot of action, as in all the 309 Clues books, and lots more secrets and mysterious characters. (Do you think Evan can be trusted? Why did they find a Lucian symbol in the factory? How old is the Vesper family? Could they really have had something to do with Mount Vesuvius?) Ah, there's a lot to figure out! (Although this book is not perfect--I had a very hard believing that the art thief, who had taken so much trouble to steal that painting, would stop looking for it because Dan "crashed" the boat)
And I've never read any of the Amulet graphic novels but you made me really curious now! May have to go and check them out.