The story follows Rachel who is taking the train, watching the same houses pass by everyday. She loves to see one particular house, because it reminds her of her past life, before she got divorced. She calls the people living in it Jess and Jason. One day she sees Jess kissing another man. The next day she hears about the missing Megan Hipwell and Rachel knows from the address in the newspaper that Megan is Jess. 
The story gets told from three POVs. Rachel, Megan and Anna. I liked to get those different looks onto the story. Rachel has an alcohol addiction which made her a very unreliable narrator. I enjoyed how the story unraveled and Rachel slowly regained her memory from the night Megan went missing. It is definitely a thriller with a slower pacing which I don't mind but I was missing some turns that made me rethink my theories. My reading experience was definitely better than what I heard about the book before. The Girl on the Train was a quick and easy read for me and I enjoyed my time reading it but it was nothing groundbreaking.