Shelter by Harlan Coben

The novel follows Mickey Bolitar, a teenager grappling with the recent death of his father and his mother's struggles with addiction. As he adjusts to a new school, Mickey becomes entangled in a mystery involving the disappearance of a fellow student, Ashley. With the help of his new friends, Ema and Spoon, Mickey uncovers a web of secrets that connect to a mysterious old woman known as the Bat Lady, who hints at deeper truths about his family's past. As Mickey delves deeper, he confronts dangerous adversaries and uncovers shocking revelations that challenge his understanding of trust and loyalty.