The Furnace and Above

Sam atones for his mistakes by saving the world. The Cage is a place of nightmares, and it tears him apart. Dean is left behind, safe and broken. They both face battles, but even so, their only solace is in each other. This is how it happens. Warnings for the Cage (torture and stuff). Really, this deals with what happened between season 5-6, but the Cage is mentioned up to s7.