In which Castiel wonders what would have happened had his vessel been female, and Sam really thinks he should discuss that with Dean.
When Charlie goes out of town, Dean is left to take care of her cats. "Maybe bring Cas over?" She had called over her shoulder as she left. "He likes cats, right?" And she'd winked. Dean had tried not to think about the wink.
Castiel has never fancied himself the online dating type. And he still doesn't. He's just looking. Definitely just looking.
They've finally, finally made it to this point—after years of staring matches and sleepless nights, fighting and aching and hoping, after Raphael and the apocalypse and motherfucking purgatory, all of the shit they've been through together—they've finally made it here, and Cas has to be a fucking gentleman.
After Castiel sacrifices his grace to cure Dean of the Mark of Cain, Dean is furious. They avoid one another, gradually growing more and more distant until Sam can no longer stand to watch it. Cas gave up everything for Dean, and Dean has been saved, and it's all for nothing. They're hardly any better off than they were before. With a push from Sam, Castiel realizes there's really only one way for Dean to understand the nature of his sacrifice. He takes him to the garden.