An inquiry into Doomwatch is begun following the events surrounding Ridge's breakdown. Meanwhile, Quist is summoned to a large country estate in Scotland, where he finds himself offered a new position with both power and wealth in the private sector, but only if he will curtail his investigations into a new drug called disocyanate. Back in London, the Minister decides that it is time to place his own man within Doomwatch, and so despatches Commander Neil Stafford to join the team.