Dean eventually realizes that his "perfect" life is an illusion maintained at the cost of the people he would have saved in the real world.
In this episode, Dean Winchester is attacked by a Djinn and transported into an alternate reality where his mother is still alive and he leads a "normal" life—free from hunting. [S5E3] What Is and What Should Never Be
The title is a direct reference to the Led Zeppelin song of the same name from their 1969 album, Led Zeppelin II . The song was written by Jimmy Page and Robert Plant and is known for its shifting dynamics between quiet, melodic verses and heavy, driving choruses. Episode Overview: Supernatural S5E3 Dean eventually realizes that his "perfect" life is