Castiel has a pain in his chest. He wonders if there is something wrong with his vessel. Upon careful examination he can find no physical damage, internal or external. Likewise, his Grace bears no sign of injury. The pain is not sharp, but ebbs and flows; a dull ache. At times it is nearly absent, falling below Castiel's notice. Other times it is raw and throbbing, demanding his attention. The latter times always seem to coincide with the presence of Dean Winchester. Castiel wonders if Dean is carrying a cursed object. An examination of Dean's person indicates that this is not the case. Also, Castiel must remember to respect other's freakin' personal space.

Castiel approaches Dean's brother, describing his condition. He has known Sam to be a man of knowledge and compassion, despite his demonic history. Sam's eyes are full of concern as Castiel informs him of his pain, but hold no answers until he mentions his brother. Castiel assures him that yes, he feels the pain most acutely when near to Dean. Sam's eyes soften to something like pity, but his voice is warm when he advises that Castiel tell Dean what he is feeling. Castiel is unsure. Dean is not a medical professional. But Sam assures him that his brother will know what to do.

Dean's expression is wary as Castiel informs him of his pain, bright and aching in the man's presence. It spikes as Dean lays a hand on his chest, his touch light as the throb of Castiel's heart beats just below the skin. Yes, Castiel tells him, eyes falling shut, that is where it hurts. Castiel hears the soft rumble of his name and feels the warm press of fingers against his cheek before a set of lips brushes against his own, and the pain within his chest bursts into a million points of light.

As he returns Dean's kiss, Castiel realizes the error in his original assessment. As he lays his hands on Dean, he searches for the right name for the beautiful ache in his chest. When Dean takes him into his bed, he teaches Castiel a new vocabulary; that of heated skin against skin and taut muscle under searching fingertips. As Dean moves inside him, Castiel comes to understand some terms that might describe the burning light that spreads from his chest to fill his being: Want, need, lust, longing. The right word comes to Castiel in the hours that follow, whispered against his skin by the man who carries the twin to Castiel's pain in his own chest. Love you Cas.