Three very strong main characters live what appears to be completely separate lives. Over the course of this story, their lives become intertwined in dramatic and tragic ways. What’s the connection? In short, it has something to do with organ donation.
The Fifth Vial has a rather large amount of characters in it. I suspect Game of Thrones has way more characters than this book did. If you could keep track of all of them, you will have no difficulty with The Fifth Vial. For me, the book was easier to comprehend once I’d managed to figure out which characters were the most important.