20 victims, throats slit. no connection. no suspects.
you awaken and then think 'holy bacon it was all a dream.'
then you're the 21st victim.
but the killer absorbs the victims minds.
you are and arent the killer.
in a moment of control in the court, you state this.
however, the killer is forced to plead insanity.
by helping the case, you gave the killer a lesser sentence as he isnt insane.
you now kill the unjust judge and jury.
then realise that you travelled through time, and killed the identical, split-at-birth twins of the actual people when you get to 21: yourself.
you were the killer all along...