This is about a college-bound boy who logs into his mother's email one day during his senior year, and finds out she's having an affair with a musician. His discovery becomes an obsession, and he tracks the entire affair through their emails, printing out their emails, pouring over them, piecing it all together. He obsesses over this affair for a long time, long after it has ended, even, and yes, it's creepy how often he imagines how his mother acts with his lover, and what they do together.
His sister is also obsessed with an idea - she's a 13-yr. old Civil War reenactor. Their father nurtures her obsession, and it's interesting following the parallels between brother and sister as the story unfolds.
I did laugh out loud at some points, and I found a certain comfort with his obsession. When you're that age, and you have an idea or a feeling that just tugs at you for months on end and you can't let it go. You nurture it, you feed it. You overanalyze, you study, you turn it around and around too much, and that's part of growing up, figuring out the puzzle or learning to let it go.
I thought it was sort of skeevy, not always believable, especially from the voice of a teenage boy, but interesting.