This is objectively a decent book, but it's not quite what I expected or wanted after reading the blurb. There is a mystery here but it doesn't actually feel like the focus of the story - Twitch stumbles into events but he never feels like a natural sleuth the way Hal does in Leonard's Adventures on Trains series. I would say the focus is much more on friendship and especially dealing with bullying (plus plenty of birdwatching). Those are great themes for a kids book, they just don't appeal to me as much as an adult and as someone who doesn't read a lot of contemporary fiction. 

The pace is fast, the characters are engaging and the story is well told. It just sadly wasn't what I was looking for, and that's probably more to do with the blurb than the book itself.