is why itâs so vitally important that they should be rooted out.â
âAnd you want us to do the rooting?â said Rosie. âI donât think so!â
âSurely thereâs got to be some kind of treatment?â I said. âSome kind of tablet people could take? Thatâs what happened when our cat had worms, we gave her tablets and then she was all right. Theyâre probably working on it right now.â
âI wish it were the case,â said the captain. âUnfortunately itâs not. Apart from anything else, no one on your world realises that these bugs exist. Not even those who have been taken over by them.â
âSo⦠How dâyou get rid of them? You donât have to
kill
people?â I said.
âNo, no!âThe captain sounded quite shocked. âThe aim is to destroy the bugs, not the people.â
âAnd thatâs what you want us to do,â said Rosie. She gave a little snort of laughter. âLike weâre the SAS, or something.â
I wouldnât actually mind being in the SAS. It is in fact my second ambition, my first onebeing to join the space programme.
âRest assured,â said the captain, âthe only violence will be to the bugs. Once they have been eliminated, the people quickly return to their normal selves. They donât even remember being taken over.â
âAnd you know this how?â said Rosie.
âTrust me,â said the captain. âI speak from experience. This is far from being our first mission. We have been patrolling this part of the galaxy for over a decade â ever since the bugs started arriving. We know all their nasty little habits. Theyâre mean, theyâre vicious, and they have to be stopped!â
âHmm.â Rosie looked at him with narrowed eyes. âHow can you tell when a personâs been taken over?â
âThere are signs. Sudden unexplained changes in behaviour, for example. We keep a close look out. We are constantly checking your news bulletins, computer blogs, anything which might alert us to the possibility.â
âBut how can you actually
tell
?â
Rosie really knows how to keep at it. But I was quite interested in hearing the answer myself.
âWe observe,â said the captain. âWe investigate. Itâs not always easy. In some cases, it can take several months before we know for sure.â
âYou still havenât said
how
,â objected Rosie. She was starting to sound a bit querulous. âI mean, someone could just be going mad, in a quite ordinary sort of way. How do you know theyâre not just going ordinarily mad?â
âWhat it comes down to, in the end, is finding physical evidence. Let me show you.â
The captain tapped again on his wrist, and the back of someoneâs head appeared on the screen. Someone with long blond hair covering their neck.
âWatch,â said the captain. We watched, as a hand snaked across the screen and carefully scooped the hair out of the way. âYou see that?â He pointed at a tiny red mark on the back of the neck. âThatâs the evidence we look for. Let me magnify it.â
The tiny red mark suddenly became a gaping hole, in the middle of which could be seen the wriggling legs of one of the centipede things. It made me feel peculiar, just looking at it.
âThat,â said the captain, âis one we managed to catch as it was burrowing its way in. Nasty littleblighters, I think youâll agree.â
I saw Rosieâs hand go up to feel her neck. She caught me watching her and immediately pretended to be fiddling with her hair.
âOut of interest,â said the captain, âyou might care to see a few of the people we know for sure have been taken over. For instanceâ¦â
A face flashed up on the screen. Blimey! I recognised it as belonging to an MP that Dad particularly hated. Every time the MP opened his mouth, Dad went