Come in me, my Angel (слэш)

As Sam and Dean run out of the hotel to get Kali out as Gabriel told them to, Sam finds himself incapable of just leaving their saviour behind. Lucifer could kill him! And even though he'd told never Gabriel anything, and they were just saving the angel's ex-girlfriend, he could not let that happen. Then he has an idea that changes their course to stopping the Apocalypse forever.