The boy who knew the ending

Seventeen-year-old Rowan Vale, a quiet literature student with a fascination for astronomy, writes a story about his English teacher's brutal death - right down to the smallest detail.
Three weeks later, it happens exactly as he wrote it.
He doesn't run. He doesn't defend himself. He simply says,
"I warned her,"
and hasn't spoken since.
Now, Mira Lennox, a psychology intern desperate to prove herself, is assigned to his case. She starts reading through his old journals - messy handwriting, half-finished stories, physics formulas crossed with poetry - and realizes he's been writing other people's deaths for years.