Those Aren't Your Wings

Dean and Castiel have shared a secret since they met - the hunter can see his angel wings. The rareness of their profound bond allows Dean to perceive a lot about Castiel that other humans cannot and he's always kept it a secret, even from Sam. But when Castiel returns with another angel's grace inside of him, Dean finds himself strangely territorial. He decides he's had enough of pushing Castiel away, once and for all. Castiel ends up teaching him more than he ever expected.