A completely unique and captivating thriller attempt, masterstroke!

This detective story is completely atypical:
Rachel, a young divorcee in roommate, drifting, alcoholic takes the train every day to get to work. His brand being stopped a few minutes every morning just outside the back of the house where she once lived with her husband. On the terrace of another nearby pavilion, she noticed a young couple "glamor" who has breakfast each morning. She invents them names, Jess and Jason, a romantic story and they fill the abyssal emptiness of his life. One morning, disappointment, Jess is on the terrace, kissing a man who is not Jason. A few days later, newspapers revealed that Jess, whose real name turns out to be Megan, disappeared alarmingly. Rachel decides to investigate ...... But who is interested in the ravings of a desperate alcoholic and incoherent? Yet it holds in a corner of his memory the truth about the disappearance.
Well written and captivating from the 1st to the last page, I was fascinated by the story that comes out of all classics.
Amateur English-speaking police officers, this is my best novel for a long time, I think this is the first novel of this former journalist, a "masterstroke" I'm already looking forward to reading the second.