Two girls get on a train across Europe. When they get off, they are no longer who they say they are . . . A brilliant YA thriller from the author of The One Memory of Flora Banks and This Summer's Secret, Emily Barr

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 . . .