When Sam was four and Dean was eight they stayed in a motel with an old creaky tree outside the window. Now Dean already knew a tree was a tree and when your bed is surrounded by rock salt you're pretty set for the night, but Sammy was not in on this lesson just yet. All he could see were the long shadows reaching for him in the dark, and his dad was gone again tonight. Did the shadows get him? He cowered into his pillow and scooted closer to Dean – his brother could protect him from the dark.
When Sam was twelve and Dean was sixteen they were on a hunt in the woods and it was their turn for lookout. Now Dean knew not to stray far from the tent and their dad's sawed off shotgun, but Sam was still too curious to stay in one place. The next thing he knew he was lost in the thicket and there was rustling in the bushes. Was he the one being hunted now? He sent up a flare and drew himself a salt circle to wait in – his brother would find him in the dark.
When Sam was twenty-two and Dean was twenty-six they found the nearest possible motel after an exhausting hunt. Now Dean already knew Sam wasn't okay and when you're fiancé gets killed in front of you you're bound to have some sleepless nights, but Sammy was still insisting everything was fine. But when his slumber was filled with screams, fire and death and his face was covered in tears he just couldn't pretend. Would this torture ever end? He woke with a strangled cry and gripped onto Dean's shoulder – his brother sat with him until it was no longer dark.
When Sam was twenty-four and Dean was twenty-eight they sat on the Impala and watched the stars dance and burn overhead. Now Dean already knew that his clock was winding down and that he had to enjoy every night's sky and sunrise he could, but Sam would refuse to accept his brother's time could come to an end. Wasn't there somebody out there who could help? He accepted the beer Dean passed him and tried to scramble for a plan – he WOULD find a way to pull his brother from the dark.