All That's Missing by Sarah Sullivan

Arlo lives with his grandfather, but his grandfather's mind "travels in time." He forgets things, and it's getting worse. One evening, Arlo's grandfather doesn't come home, so Arlo sets out in the rain to find him. The police meet Arlo in front of the house and tell him that his grandfather is in the hospital. He had a stroke, and a social worker wants to put Arlo in a shelter. Arlo decides to run away to find a grandmother he hasn't seen since his parent's funeral, when he was two. He has no idea what will happened when, or if, he finds her.

Arlo is an interesting character as he struggles to hide his grandfather's mental issues from everyone else. He struggles in school, but he has a great heart. The conflict is unique, although the adults are pretty naive. What the plot lacks in action it makes up for with sympathy and concern for Arlo.