There's no such thing as the perfect alibi

'Recently, he was the subject of a failed assassination attempt, an honour you have never quite earned'

Today I am bringing you a complete novel. It is not just a complete novel – it is also an interactive novel. What this means is that you, as the hero, have to choose the right option at certain points before you can continue with the story. Does that make sense? Well, you'll get the hang as we go along.

Now, in the novel your name is Professor Victor Lewin, and you are a leading expert in the kind of biology that leads to germ warfare. As a top dog in science, you should be as happy as Riley. Unfortunately, life is always a bit more complicated than that, isn't it?

Yes, it is. So to find out more, let's get stuck into the novel, which is entitled: "Murder By The Book".

YOU ARE a world expert in germ warfare. You sometimes jokingly say, "Of course, if you're a germ, it's always warfare!", and people laugh respectfully. But it's a serious business, and you are seriously good at it at your university research laboratory, which is not far from Oxford railway station. Top Iraqis often come to consult you, as indeed do top British politicians, and occasionally you are the subject of kidnap attempts by international agents, which is very flattering.

But there is one grim shadow on your horizon, and that is:

a) Your innate lack of dress sense.

b) The increasing realisation that your wife, Sheila, is the most boring person this side of Cambridge.

c) Your inability to enjoy opera.

d) Your rival, Professor Mortensen.

Yes – that damned Professor Mortensen! If you, Victor Lewin, are the world's biggest and best germ warfare man, then Ronald Mortensen is the biggest up-and-coming germ warfare man! And the noise is that he has recently come up with a sensational new discovery in the field of nerve paralysis! And quite recently Mortensen was the subject of a failed assassination attempt, a scholastic honour which you have never quite earned.

Well, you have got to do something about the Mortensen threat. It shouldn't be too hard, as Mortensen works in a nearby lab in Oxford. But what course should the action take? What should you do to neutralise the threat of this brilliant young performer?

a) Put about a rumour that he is pro-fox-hunting

b) Tell people that he is going to give it all up for a TV series

c) Get him round to dinner and have his brain destroyed by conversation with your wife, Sheila.

d) Murder him.

Yes, the more you think about it, the nicer it would be to eliminate him by a good old-fashioned murder. After all, people will only think it was an international murder plot. And you, as a top scientist, should be able to devise the perfect murder method. And then, one day, as you are giving a lecture, you suddenly see how to give yourself the perfect alibi! No one will ever suspect you of the killing of Professor Mortensen if, at the time of the crime, you were:

a) Up in a space shuttle.

b) Getting a knighthood from the Queen

c) Killing your wife, Sheila

d) Giving a lecture

Yes, if you were giving a lecture, you will have two hundred students ready to swear to your alibi! And yet, you reflect excitedly, it would not be so very difficult to fake your presence at your own lecture. If it takes place in the dark, and the students can see nothing but slides, and your voice, sounding amplified, is actually is pre-recorded, nobody will ever know that you have slipped out for half an hour to kill Mortensen!

And so it turns out. You find a time when Mortensen will be alone in his lab. You set up the lecture alibi. You slip out halfway through and kill him. And you return to your lecture hall! Unfortunately, in your absence:

a) It has burnt down.

b) The slide machine has broken down.

c) The tape machine has broken down.

d) The Iraqis have declared germ warfare on the West, and MI5 have come to get you urgently, and found you weren't there.

Yes, I am afraid germ warfare has broken out, and you suddenly realise that your alibi has been blown to bits, especially as MI5 are no doubt even at this moment going round to summon Professor Mortensen...

I'm sorry. We have run out of space. You are on your own now. Good luck!