the air smells like the promise of tomorrow and nothing has ever smelled more terrifying

Guardian angels aren't supposed to show themselves, they're supposed to look out for their human and guide them away from mistakes, maybe save them from an unfortunate end, and if they die, they're assigned a new human.However, Castiel can't help but feel attached to his human, Dean Winchester, and when Dean finds himself facing death, Castiel shows himself to save him. Then when Castiel finds himself falling in love with his human and accidentally locks himself out of heaven, things start to spiral out of control.