Tom sat in maths class, hunched over a triangles worksheet and ignoring Adam Flint's attempts at conversation. If he finished this he wouldn't have homework tonight. He heard the door open and looked up, breath catching in his throat. Standing in the door was Alex Rider, silently waiting for the teacher to notice him. Alex was home! He looked rather tan-perhaps MI6 had sent him south?-and he held his left arm carefully away from his chest. Tom watched Alex sit in the back of class, avoiding Tom's eyes. Tom's chest constricted. What had happened to Alex while he was away?