Sam and Dean heard there was a weapon being made, they didn't know what but they heard from a demon it was to start the apocalypse again. Dean called Castiel, now they had a basket and were driving away in Baby while Castiel tried to stop your crying.

"Can ya stop the baby from crying Cas?" Dean glanced to Castiel then back to the road as he drove.

Castiel picked you up from the baby basket and rocked you gently, holding you closely but not completely sure of what to do. "I'm trying."

"Maybe it's hungry." Sam shrugs and glanced back at Castiel.