A giant problem - Tony DiTerlizzi

Nick and Laurie have a giant problem and it's a lot bigger than they originally thought. When Taloa sent them off to find her sisters, they discovered a single fire breathing giant, but as it turns out, that one giant is just the tip one the proverbial iceberg. According to NoSeeum Jack, the blind giant killer who helped Nick, Laurie, and Jared dispatch the original giant, there are hundreds, possibly even thousands of giants underneath the surface waiting to wake up. And since Taloa refuses to give any assistance until her sisters are located, the kids turn to a kingdom of merfolk for help which inevitably means that there's trouble on the way!