They make a friend; her name is Trudi de la Rosa. She’s a wannabe detective-type too, but honestly, she’s less of an idiot than the brothers.
The three of them team up to solve a mystery that takes place in a snowy chateau up in the mountains. It gets more complicated around chapter 11, but now you’ve got the main gist of it. The story’s full of intrigue and adventure and puzzles and light violence and some swear words. It’s really entertaining.

Just buy the book and start reading.
You’ll understand everything about the Ghost Hunters Adventure Club very soon.