Richard Jane is a diver working on an off-shore oil platform in the North Sea when something happens and he loses contact with the surface. He finds that a terrible accident has occurred and that the whole crew is dead or dying, with everything burned. It becomes apparent that 'The Event' isn't restricted to the rig when he reaches the mainland.
The first half of the book concerns Jane's journey from near Aberdeen to London, where he hopes to find his young son alive. The author does a great job at portraying the desolation left behind (event if the effects of the 'fire' are somewhat inconsistent) and we really start to feel Jane's desperation that his son is OK. This part of the story is great, and a good example of a post-apocalyptic novel.
However... without spoiling things, the second half of the book gets a bit silly in my opinion. There is a fairly drastic change of pace and the story becomes more of a horror story. This would be fine in itself, but the two halves of the story don't really hang together.
On top of that, like others reviewers have said, I really didn't understand the ending. The last few pages felt like the author was late for something and just scribbled down the ending quickly, with little care, which I'm sure wasn't the case. I'm sure he understood what was going on, but I felt a bit let down.
In summary, not a bad book. There is a conclusion of a sort, but don't expect an amazing ending.