Adam had been possessed by the Arch-Angel Micheal, and locked in a cage with Lucifer.

Sam got out safely, and now, Dean and Sam didn't seem to even care that their other brother Adam, was locked in the cage still. But you were not having it. You didn't understand why they didn't seem to care. Apparently, getting Adam out and safe, wasn't worth the risk of Micheal being free. But it was worth it to you.

So you studied and studied, and looked through every book, until eventually, you were able to strike a deal up with Crowley. Not for your soul, but for another soul he had been wanting. The one that got away.

You got a new host for Micheal, and had them bring the cage up. Adam looked horrible. Or Micheal did, at least. You were able to trick Micheal into transferring hosts, but pulled Adam out, before sending the cage back down.