In Summer of 2021, we read The Goldfish Boy, a mystery revolving around a the young boy, with OCD, who can't leave his house and stares out his window watching the world go by, until he becomes a potential witness to a neighborhood girl's disappearance.
If you think it sounds dark, it is. There are big topics about mental health, death, and the scary things in this world. It opened up for a world of conversation with the kids, which I always enjoy.
We sweetened things up, afterwards, and read Summer of Thousand Pies. It is still a mature novel, but had solid friendships and a fun plot.
I didn't organize that book club too much, and made it simple with a child-led discussion group where they came to the table with two questions of their own to ask.