Alan Willis is a lazy, unscrupulous property owner leasing dilapidated homes to unsuspecting tenants. When Australian student Claire MacGregor agrees to rent a death-trap of an apartment she promptly dies of carbon monoxide poisoning from the central heating boiler. Alan finds the body, panics, and enlists the help of his wife Liz to disguise the death as suicide. But the plan, to make it appear as if she killed herself by inhaling exhaust fumes from her car, runs into problems when the real car owner appears claiming Claire could not drive.