The Riverman by Aaron Starmer

Alistair hasn't spoken to his neighbor in years, so he's surprised when Fiona asks him to write her biography. Plus, she's only thirteen years old. She tells him of her visits to Aquavania, a world where all of her dreams come true. She creates a tropical island, flying bandicoots, paisley giraffes, and a talking bush baby named Toby. Everything is wonderful until she discovers The Riverman is sucking the souls from other kids in Aquavania. Fiona tells Alistair that The Riverman may be in the Solid World, looking for her. "A dangerous man. Missing children. A girl too scared to tell the truth."

Interesting story with a lot going on. The idea of a wonderful dream world being haunted by a soul-sucking creature is creative. Many of the characters had their own problems which muddied the plot for me. Alistair had mixed emotions about his best friend, Charlie, and Charlie's troubled brother just wanted to get out of town and start over. Fiona became Charlie's first girlfriend, and that complicated things. While The Riverman was the main conflict in the book, I wanted his character to be more of a presence in the plot. The threat of his character would have been stronger if he had actually appeared earlier in the book.