Well, honestly there's not much to say. The main characters are supposed to somehow decide who is gonna be the successor of the current god, by whatever means they decide. In the first half, there's a guy who wants to kill everybody, and the protagonist, of course, doesn't want to kill anybody, telling everybody he just wants to be happy (preferably dating the girl he likes). He gets confronted with his values over and over, until at some point, he ends up helping to kill a person. From this point onwards, the history drags itself by creating confusion and promising there is gonna be a logical closure, and guess what, it never happens. Unless you are willing to put yourself through a torture session, I don't recommend, it's a total waste of time.
Review of Platinum End
