I liked this very much. The sentences are clear and easy to read, and you vary the structure and lengths which helps the pace. You start off with plenty of action which is a good hook for young and old.

I liked Tristan, his character was attractive and both his thoughts and actions were totally what one would expect from a child. I think you understand kids, and that shows in your writing.

Your writing has an old-fashioned feel to it, and I tried to work out exactly why that was. I came to the conclusion that it might be because of the lack of dialogue. (I believe Harry Potter is about 70% dialogue!) You have used inner dialogue, T's thoughts, which helps, but otherwise, the writing is not broken up much until Chapter 4. I couldn't help wishing that T had a companion right from the start, so that they could bounce off each other, but I understand that would mean a massive re-write.

I am an ex-teacher and would welcome this book into my classroom. It is nicely written and flows well. I wish you the best of luck with it.