Devil's Helmet

Colonel Peter Challinor threatens to wipe out thousands of residents on the Isle of Man using the most toxic nerve agent ever synthesized. The hunt is on to find him and stop him, but time is short and he has plenty of places to hide.

Hugh Bottomley arrives from the Ministry of Defence in London to help out where he can. But Sparky knows Bottomley's past, and it is one that Bottomley would like kept secret. Meanwhile, house-to-house enquiries turn up more than a toxic nerve agent.

The arrival...