2 stars (It was okay).
Okay, I need to preface this by saying my son loved this. He read it with his class in fifth grade, and they worked out the puzzles in the illustrations together, and he ended up asking for a set of pentominoes for his birthday.
So of course, being the middle grade fan that I am, I had to read it. And . . . it wasn’t for me. Too much of the book was one character leaping to an absolutely absurd conclusion, the other character agreeing that of course that must be right, and then it turning out to *be* right. I like a mystery that’s hard but possible to figure out. This just felt like being jerked around.
That said, it’s not exactly a mystery. It’s a puzzle. The whole plot basically sets up the puzzle for the reader. As such, it’s not an especially good plot, though the two main characters are fine enough. But it can be a fun puzzle.
And my son–he of Rubik’s cubes and coding and science fairs–well, he’s a lot like Calder. I can see why he liked this book so much.