John Harker is running surveillance on Jake Roberts, ex-Real IRA terrorist, presently engaged in a drug-smuggling operation based along the Channel coast. Ben Parry of MI5 learns that Roberts is running a second operation as well - Greek Fire. So the two men join forces against their common enemy. They know the aim of Greek Fire - the detonation of a massive bomb in the center of one of the many towns along the Channel coast. But they don't know which town, and they don't know the timing of the strike - although they believe it is imminent.