Our bodies, possessed by light

Purged of all his souls, Castiel is a changed being, stronger than an angel and too powerful for Jimmy's body to contain. Happily, there's an archangel's vessel on hand, and he could use fixing, too. Dean isn't too happy about the idea of his brother acting as a vessel for Castiel, and Sam can guess why, but it isn't until Castiel gets inside his head and they learn to share the vessel -- and their thoughts -- that Sam realises Cas is as in love with Dean as Dean is with him. It's unfortunate that there's nothing much to be done about it now, but Castiel will get another vessel soon. The Winchesters will make damn sure of that. In the meantime, it's up to the three of them to establish their own strange accord, and Dean realises more fully than ever that it's Castiel, and not his vessel, that he loves.