The Girl on the Train

In the official trailer for the thriller The Girl on the Train, we learn that Megan Hipwell (Haley Bennett) was having a secret affair. When she goes missing, Rachel (Emily Blunt) tells the police what she saw.

While taking the train to the city, Rachel spotted Megan with a man who wasn't her husband. The police tell her that Megan was working as a nanny for Rachel's ex-husband and they know Rachel was seen in the area when Megan went missing. However, Rachel can't remember what she was doing there. When she isn't able to provide an alibi, the police begin to consider her a suspect in Megan's murder.