The antagonist has kind of switched in the book at this point. This is thanks to Alex's decision to switch sides. He is now training with SCORPIA, a terrorist organization in Italy. Now the British government is against him, in some ways. They don't want him to be a part of SCORPIA, but they also don't want to kill him since he has been such an asset to them in the past. MI6 hasn't treated Alex the best in the past, but this is a completely different matter. They need to preserve his safety and at the same time get him to change his mind about SCORPIA. Being fed lies from every angle, Alex is caught up in more than he can handle. SCORPIA wants to train him to be a killer, but he knows he can never be that. MI6 is desperate to get Alex back, and SCORPIA isn't very willing to give him up. A child spy is something more than one national security force has taken advantage of in the past, but now that he is in the hands of a terrorist organization and doesn't look like he is going to come back to the agency who betrayed him.