Eleven year-old Nick Vargas thinks his sucky life is being turned upside down - his father has just remarried and moved his new wife and her daughter into his home in the soon-to-be-completed, Mangrove Hollow. And now, not only has Nick lost his bedroom to his wacky new step-sister Laurie (who lugs around this huge book about faeries) - if that wasn't bad enough - Nick's father actually wants him to spend time with her!

So when an "expedition" to a nearby lake turns up a nixie with a giant problem - and by giant, we mean the enormous, fire-breathing kind - it's up to Nick and Laurie (with the help of Nick's older brother and a very familiar face from the original Spiderwick Chronicles) to come up with a plan. Will they be able to stop the rampaging beast before all of Mangrove Hollow goes up in smoke?