The Girl on the Train by Paula Hawkins

The Girl on the Train follows Rachel Watson, a troubled woman who rides the same train every day, escaping her broken life by imagining stories about a seemingly perfect couple she sees from the window.

When the woman she watches mysteriously disappears, Rachel becomes entangled in a web of lies, secrets, and psychological tension.

As she tries to uncover the truth, she confronts her own unreliable memories and dangerous connections.