A very appropriate read for middle grade or any teens that enjoy MG, I had a good time reading it. But while it was good, it wasn't good enough for a 5 star book rating from me. (Maybe I'm a little harsh but reviews need some nuance sometimes.) Let's see... I lowkey didn't know this series had a sequel till I saw the cover on the library and squealed yes please! However, I think the first book was better than this. The stakes aren't really there and the premise the story is set on, like a treasure hunt but without many clues, was disappointing. However, the characters served. I like the development in relationship between Cassidy and Tom (not romance mind you, but enemy to acquaintance). The plot twist and who the traitor was is unexpected. I was genuinely surprised, tho there weren't any clues to lead to a satisfying discovery of them being the traitor. And the thing is, I didn't even KNOW there was supposed to be a traitor. Also I wish the author had added a little more contextual hint why the Corsair had so much loyalty to the girly in Penumbra. And why go to the island now, after 15 years? Lastly, I think there should be a bigger hook at the end so people will want to read the sequel because even though a short expert of the third book is included, it doesn't make me feel like I had to read the next book.