The story begins with a paramedic, Yao, and her partner, Finn, responding to a call made from a woman named Masha who suffers from a cardiac arrest. After her recovery, she recruits Yao and her personal assistant who made the phone call, Delilah, to come work for her as they saved her life. She dedicates her recovery to a place known simply as Tranquillum House.
The scenes changes to ten years later to a woman named Frances, who is romantically unlucky despite being a romance novelist. She is invited to stay at Tranquillum House, where she meets Yao who works there now. The other guests include, Jan and policeman Gus; Carmen, who is there to lose weight; Ben and Jessica, who are attempting to use this as an opportunity to save their marriage; Tony, who is looking for a new lease at life; Lars and Ray who are having relationship troubles and; Napoleon, Heather and Zoe, a family who are struggling after the loss of their son Zach.
They are all taken to a meditation room where they are unwittingly drugged by Masha and locked in the room. Masha gives them a series of clues to get the door unlocked but they fail to do so. Masha is desperate for the guests to feel fear, which puts her at odds with Yao. Yao attempts to help let the guests out, which leads to a struggle with Masha. Eventually, the guests realize that the door is unlocked and come out. Masha and Yao are arrested and the guests manage to come to terms with their personal problems.
