Rob worries about everything - being bitten by snakes to dinosaurs waiting round the corner.

So when the Vorks move in across the road, he is convinced that they're aliens and that he must save the world!

The only person who can help is Marsha; she may be a bit weird but she is interested in astronomy!

Getting the proof they need to convince the authorities is difficult and involves embarrassing scenes at the police station, kidnap - and looking after a baby!

Finally the confusion is sorted out and Rob unmasks a much-wanted burglar and becomes a hero - this doesn't stop him worrying!