Calder is the dumbest, least effective evil merman ever, which makes sense, considering he's the main character in the book and it would not do for a group of simpering teenage girls to fall in love with a guy who would willingly drag them underwater and kill them. 
 Seriously, he's a male TSTL character. He fails at everything his sisters instruct him to do, seduce a target? Please. He falls in love with her as soon as she blinks at him. Lily is too smart for this dumb POS. I just found myself shaking my head and laughing at his every failure. The plot is convoluted and unbelievable, they're supposed to get revenge for something this one person did that made their mom suffer and die? Too far stretched, even for paranormal YA.