This was just pure genius. Seriously. The storyline was brilliant and the whole murder to who the unsub really is, was just suspense-filled.
The episode starts off fine, with the end being the beginning, then rewind 7 days and it begins with the discovery of the body by Adam. And when the BAU is called in and they discover they have a timeline since spring break is going to be over soon and the murderer might get away with the murders. The actor who played Adam/Amanda, Rathbone, plays his roles very well, you really cannot tell the difference because the he plays each completely different. They are really two different people. The voice, the behaviour, the way he acts..it's just genius. And how it's fit into the story, the whole two separate identities disorder, is brilliant. The team discover it's males who behave like alpha males that are being murdered and think at first it's a man, then think it's two people, a man and a woman working together. When they interview Adam, both Reid and Morgan have no idea he's the unsub. And even later, they still have a hard time believing it until Reid figures out the two personality disorder thing, which suddenly makes sense. I really had no idea and this revelation really creeped me out.
Reid also gets a bit attached to Adam, even visiting Amanda at the end telling Amanda he's looking for Adam. I thought that was nice, and felt sorry for Amanda who only emerges to protect Adam. And it ends.