I feel like I should preface this with two notes. Firstly that I'm admittedly biased as hell, because the book is dedicated to me (!!) and it's by my good friend Dave. (But that shouldn't stop you from reading it.) And two, that if you have excessively warm fuzzy feelings about Winnie the Pooh and consider the canon a sacred, untouchable part of your childhood... reconsider. (Which perhaps should stop you from reading it. But that's the only thing.)
This thing is dark. Quite dark, quite heart-wounding, and sometimes actually chilling, but there's enough humor and plot to keep it from dissolving into a strange mess.
To begin with, "Angle of Dath" is a characteristic misspelling of "Angel of Death," which should be your first clue that this is not going to be a familiar Pooh adventure. But it's not a senseless "darker and grittier" parody either - there's no grimdark for edginess' sake. Actually, I'm thinking "Parody" might be the wrong word in this case. It's not a mockery, it's an expansion, exploring an inevitability (Christopher Robin's growing up and moving on) and taking it to its logical, devastating conclusion.
It's about loss. It's about abandonment, and the coping mechanisms that come from overpowering grief at being left behind by somebody you love. Christopher Robin, this godlike prince child, has gone from the 100-Acre Wood, taking springtime and joy with him, leaving his animal friends to pick up the pieces. And they respond with depression, desperation, teenage rebellion, alcoholism, and lashing out at each other. In short, not like toys, but like humans, whose hearts have been broken. Or, rather, with an enduring childlike, toy-like innocence that makes it all the more heartbreaking.
Without spoiling - and my goodness, but there are plot twists - the title comes from a mysterious and deadly figure in black now stalking the 100-Acre Wood, and brutally murdering its inhabitants. The one thing I can tell you is the killer's motive - the Angle seeks to perform a dark ritual, fueled by blood, heart and stuffing, to summon the boy-god Christopher Robin back, and transform the Wood into a golden land of eternal summer and playtime.
Like I said, if you consider Winnie the Pooh untouchable and sacred, not the book for you. But if you want to see these beloved characters suffering through realistic stages of grieving and trauma (and I'll be honest, that's one of my favorite things!) while remaining essentially in-character, absolutely give it a try. (Tigger is still believably Tigger, even in the midst of harrowing self-doubt.) It's a strange ride, but a good one.
Then go give your stuffed animals a hug, and promise to never leave them. You'll save all parties a great deal of grief, and possibly homicide.