S12·E5 Under Dark Stars (1)

A sunburned Dalziel returns from holiday in Australia and finds himself immediately investigating a murder. The dead man is Declan Roach, a researcher at the local university found in a laboratory clean room. The autopsy confirms that he died from nitrogen intoxication but it is unclear at first if it was accidental or not. Roach was working under the direction of Professor Frances Cunningham, who in turn has a major contract with Aphrodite, a major cosmetics firm. She's working on a formula for a rejuvenation cream that will be nothing less than a fountain of youth and there's obviously a great deal of money at stake. Dalziel, meanwhile, is thinking of packing it in and emigrating to Australia.