William Sleator - Others See Us

Summary:

Jared's summer vacation has just begun. Tonight he will finally see Annelise, the beautiful cousin he's been dreaming about all year. But now, on the first ride of the season, Jared improbably wrecks his bike, falling into a swamp filled with toxic waste. Later, he begins to notice voices in his head. Strange voices... almost like other people's thoughts.

What follows is a murderous battle of minds, wills, and family relationships where there is no turning back—and no place to hide from the swamp's toxic powers