Emily is on holiday with her best friend, Kristen, in the stunning mountains of Chile. They're having the time of their lives until, on the last night of the trip, Emily enters their hotel suite to find it covered in blood.

Kristen claims a backpacker attacked her. She shouted, but no-one heard. She struggled, but he was too strong.

She had no option but to kill him.

With no evidence of the assault, Emily must help her hide the body. . .

Back home, Emily tries to forget what happened, but a surprise visit from Kristen forces her to confront the events of that night.

As the walls close in on their cover-up, Emily asks herself: can she really trust her closest friend?