June Cryer is a shopaholic suburban housewife trapped in a lousy marriage. After discovering her husband's infidelity with the flight attendant next door, she loses her home, her husband and her credit rating. But there's a solution: a friend needs a caretaker for a spectacular London high-rise apartment. It's just for the weekend, and there'll be money to spend in a city with every temptation on offer. Seizing the opportunity to escape, June moves in only to find that there's no electricity and no phone. She must flat-sit until the security system comes back on. When a terrified girl breaks into the flat and June makes the mistake of asking the neighbours for help, she finds herself embroiled in an escalating nightmare, trying to prove that a murderer exists. For the next 24 hours she must survive on the streets without friends or money and solve an impossible crime.