More subpar plot and implausibility (and for a kids' fantasy novel at that)! First, there was hardly any buildup to Emily's and Aaron's relationship - without any convincing chemistry, they suddenly ended up together, then just as suddenly broke up for the stupidest reason ever. Second, the author didn't keep track of her magic system; if merpeople can't swim in freezing Arctic waters without special potions, why wasn't Shona frozen solid when she tried to follow her friends there? Makes perfect sense. And third, so many side characters behaved in inconsistent ways that we're just supposed to accept - Archie suddenly turning sketchy and suspicious; Archie's behavior going over Emily and Aaron's heads; Emily and Aaron's clearly-not-vacation going right over their parents' heads; Neptune suddenly deciding to trust two kids he previously deemed troublemakers with an all-important mission, as if he isn't a god-king himself. Unfortunately, each fan-requested installment to this series seems to come with a corresponding decline in quality. The first book, despite its occasional flaws, still remains the best of the series in my opinion. But I guess I might as well finish the books since I've made it this far already, and I'm morbidly curious to see how this series could possibly be wrapped up at the end. ( )