They were the most notorious murder for ten years. But when Spencer Reid entered the BAU, things dramatically changed. His high IQ and bright ideas weren't a match for them.

Or were they? No one knows why the killer started slipping up.

But there is another one. Another killer who's striving to be better and who's got the same MO as them.

And the BAU needs their help. Even if their locked behind bars. Spencer walks through the prison corridors towards their cell since they only talk to him