'The Girl on the Train' First Trailer Features a Frightened Emily Blunt

"I'm afraid of myself."

The Girl on the Train released its first official teaser trailer on Wednesday and the preview is full of suspense and intrigue.

Emily Blunt stars in the film, directed by Tate Taylor and adapted by Erin Cressida Wilson from Paula Hawkins' bestselling novel. Blunt plays Rachel Watson, an alcoholic woman whose life has fallen apart and who is struggling to recuperate following a devastating divorce from Tom, played by Justin Theroux.

Rachel watches the lives of a seemingly perfect couple as she rides the train daily, but circumstances go downhill quickly. She gets caught up in a mystery involving a missing girl, Megan Hipwell (Haley Bennett) and a night she can't fully remember.

"What happened that night in the tunnel, tell me the truth," a desperate Blunt says in the trailer.  Toward the end of the video she admits that she's scared of herself. Blunt's performance is gripping and the video is sure to leave devoted book fans wanting more.

The film, from Universal Pictures and Amblin Entertainment, hits theaters Oct. 7.