On this episode of Supernatural…
Sam gets a visit from his imaginary friend Sully.
Someone has been killing of “imaginary friends” or Zana.
Sam and Dean investigate and discover that one of Sully’s former children was killed by accident and he blamed himself. The child’s twin sister hurt his friends and was coming after Sully.
Sam reveals to Sully his fears and talks about facing the Darkness.
Flashbacks reveal Sam and Sully bonding while Dean and John hunt.
Sully suggests Sam try a different life.
Sam ends his relationship with Sully when he gets the call to go on a hunt.
Sam and Dean stop the twin from killing Sully.
Sam brings up the visions to Dean again. He asks Dean what other way there is to stop the Darkness.