This book for younger readers has some things which will appeal to its target audience (particularly many scenes of muck and bugs crawling on things), but I at least bounced off the structure and main source of conflict behind the story.Jack and Jaide are twins, with a perpetually absent father and a cross mother, who receive a mysterious letter from their previously unknown "Grandmother X" addressing them as "troubletwisters" and expecting to see them soon. This is a forewarning of disaster, as an extremely strange, overwhelming and scary incident sees them off to live at Grandmother X's for a while.Problems I had with the story:1. Cross and grumpy Mum who has married someone with powers (learning about this afterwards), and thinks the best way to deal with it is denial, being cross and grumpy, and shutting down any conversation about the situation. This is something I've seen before and one which annoys the hell out of me. But particularly here when Mum is a paramedic and, one would presume, has an ounce of chutzpah. If strange magic things make your house blow up, and this relates specifically to your children, putting your hands over your ears and going La La La is not the way to protect your children.2. Conflict driven almost entirely by not telling the protagonists what's going on. Apparently negative consequences could arise from providing "troubletwisters" with a clear, sensible and timely explanation of what they are, what they're facing, and what they should and shouldn't do. Instead we have hidden tests, memory erasures, false suspicion, drama which arises entirely because of the kids not knowing what's going on - and all because of possible negative consequences of being told beforehand (troubletwisters are the children of "Wardens" whose powers are not yet under control and who might therefore warp 'magics' around them). HOWEVER, given that the creatively named "The Evil" is actively hunting the kids, I can think of a few clear and obvious consequences of NOT telling them what's going on.3. The whole "negative consequences" argument falls down once you realise that most children of Wardens would have to have a pretty damn good idea what their parents do unless they have one of those cross and grumpy in denial Mums. AND the grandmother's tendency to address the children as "troubletwisters" and then act mysterious when they ask her why. [A thing just as annoying as Doctor Who's River Song carolling "Spoilers!" at every opportunity.] Since being a "troubletwister" is simply a phase kids of Wardens go through where they don't have control of their powers (ie. an analogue of being a teenager), it is simply weird to have not only their grandmother but suddenly their own father addressing them as "my dear troubletwisters". It would be like saying "my dear teenagers" to your own kids.4. All this could perhaps be saved if the kids themselves were interesting, or if there was an enormous amount of delight and wonder invested in the magical events and new house setting they find themselves in. Instead we have a focus on action, weirdness without wonder, and two kids who come across more as being opposite traits rather than being interesting people who we care about.So, as a story it might work for kids who like lots of dramatic encounters with bugs, but it read overlong and contrived to this not-kid.If you want to read a Nix middle-grade, read the Keys to the Kingdom series, which is head and shoulders above this story.