A vicar collapses during a sermon, and there are seemingly unrelated events, one involving John Ridge. The answers are out there, but are obscured by big business and profit margins.

Doomwatch is alerted to a laboratory where a new toxic gas is being developed for military use, available in a 'handy' aerosol can for easy application during conflict. But Quist and Anne's enquiry soon leads them to doubt that the scientists' safety measures concerning the storage of the gas may not be as secure as they think.