The day stretched on, and everyone's mood in the Impala was as grim as the clouds outside. A starless night eventually enveloped them, and Castiel asked Dean to pull over at a sporting shop.
"We're going camping?" Dean said when Castiel instructed him to buy a tent and a few other camping supplies.
"Possibly only for tonight," Castiel said. Castiel walked down the aisles of the store, looking quizzically at the numerous types of equipment. "I hope you know what is needed for camping, because, I do not."
Later on, as they were setting up at a remote campground, Castiel announced his departure. "It is time for me to go." He had already approved of the spot, no one else was camping anywhere near them for miles.
"Cas, how on Earth is camping going to hide us from angels in heaven?" Dean asked.
"I told you Dean, do not ask me. I will not tell you, it is for your protection. Tomorrow night you might be able to stay at a motel again. I am going to go now, and am hoping to be back by tomorrow morning. Continue to head to the mountains if I do not arrive as scheduled. Dean, I need for you to speak to me alone for a minute."
Dean and Castiel walked off a ways until Sam, who was still setting up the tent, was out of earshot.
"What I am doing is incredibly dangerous, Dean. It is possible I will never be back. I was serious when I told you that we would be hunted and killed for what we have done. However, I am hoping that heaven's attachment to you being the one to stop Lucifer buys us a little more time."
"Cas, you have to come back," Dean said. "I can't just bump off Lucifer with a salt gun or a exorcism ritual. I need details. I need help. I mean, me? Fighting Lucifer? You gotta be kidding me. I can handle your average six-pack demon squad or a bunch of bloodthirsty vampires that like to snack on more than Edward Cullen does. But Lucifer? The devil himself? This is too much. I'm just a man, Cas. Maybe some of that ridiculous prophecy can help us."
Dean was quiet, thinking for a moment. "Maybe Chuck can help us."
"Chuck probably knows things that would be very helpful to us, but right now it's out of the question with the archangel by his side. I am going to do my best to come back, Dean, with some answers. For now, I want you to think of a code phrase that would be entirely out of character for me to say. Something just between you and me. If you need me to verify who I am later, ask me for the code phrase."
"And how do we know enemies aren't hearing the code phrase right now?" Dean asked. "And are you saying someone who looks like you but isn't you might come back instead?"
"We need to be open to all possibilities, Dean, as unfortunate as they could be. I will make sure no one else hears or knows of the phrase. Remember too, what I said about Lucifer will most likely be in a vessel. And he will appear likeable, and may try to put you under a spell, so to speak, like the Siren did. I highly recommend that you stay away from certain kinds of female company for the time being, Dean."
"What, are you jealous?" Dean blurted out without thinking. Castiel looked down "Look Cas, I know this isn't the time for rolls in the hay! I'll be really careful who I trust, okay? But when can we call Bobby or stop to see him?"
"I'm going to try and reach Bobby through dreams. I will lead him to you, if I can. Now what is the code phrase you have chosen for me to remember?"
"Um, I don't know. How about 'Eat my shorts?'"
"Eat my shorts. What an odd saying. Very appropriate. I would never say that. Okay, goodbye Dean. If worse comes to worse and you don't see me again, start researching. Try to find out on your own how Lucifer must be stopped. If it is God's will, you will find an answer, even without me."
"Cas?" Dean said.
"Yes?"
"I do hope I will see you again. Even with you being a dick and all to me in the past, I feel like I can count on you now. It's hard to imagine going through this without you, actually."
"It is for that very reason I am going to be as careful as possible. Goodbye, Dean."
"Good luck, Cas."
Dean watched the space where Castiel had stood turn into air. Then he turned around to go help Sam set up camp.