The Other Girl by Emily Barr

Discover the gripping new YA thriller from the bestselling author of The One Memory of Flora Banks and This Summer's Secret. Two girls meet on a train journey. One of them - privileged, chaotic - is heading to an exclusive Swiss rehab centre following months of partying and living wildly.

The other - who couldn't be more different - is down to her last penny, running away. When they get off the train they are both pretending to be the other. Just for a short period, of course.

Just until the rehab stint is over . . .