This is book number 3 in the Merits of Mischief series.
When the Kilter Academy students go on retreat with their parents, it's the more mischief the merrier in this third book of a trouble-loving middle grade series Seamus Hinkle has encountered a good deal of mystery and a lot of secrets since he first started at Kilter Academy. The longer he's there, the more unanswered questions he seems to have. At last it seems like he just might get some answers as he and his troublemaker friends prepare for a huge event: a Kilter Academy retreat in the Adirondack Mountains with all the students...and their parents. Will Seamus finally learn how his own mother is connected to Annika, the mercurial headmistress of Kilter? Will he discover Annika's true purpose for the Kilter students? And how will the students from the rival school, the Incriminators, play into all of this? It's hard to say, but one thing is for sure-there will be plenty of trouble along the way