Castiel heard Dean calling him, even though he pretended he didn't for the first half hour. Dean's prayers started getting more and more boisterous, anything to elicit a response from the angel. Eventually, Cas couldn't focus on anything else and flew down to join Dean on Earth. He joined Dean in the front of the Impala, overlooking the sunset on a cliff face.

'Beautiful, isn't it?' Dean asked as he turned in his seat to look at Cas.

'Yes, the setting of the sun is very beautiful,' Cas agreed, slightly awestruck at his Father's creations.

'I was talking about you,' the Winchester said, 'but the sun is pretty hot too.'

'Of course, its surface temperature is 9,941 degrees Fahrenheit,' the angel said.

Dean sighed, smiling. 'I've missed you, Cas.'

'I've missed you too, Dean.'

'Thank you for helping me with Sam.' Dean looked down at his hands where they were placed on his lap. 'I know you didn't have to, and I probably don't deserve help, not after everything I did, so thanks.'

'I promised I'd protect you,' Cas said simply. He still carried the guilt of letting John abuse his sons like shackles, and he was willing to do just about anything to be free of the feeling. This isn't supposed to happen to angels.

'I remember.' Castiel turned to look at Dean. He'd grown so much from the boy he'd been when Cas had first met him, and yet he was still the same helpless child, despite being 20 years old. 'Where did you go, Cas?'

Castiel shook his head. Remembered how Dean had looked when John found out Sam was gone. He couldn't believe he'd let that happen. His magic was supposed to be permanent, stronger than time, especially stronger than the fist of John Winchester. But Dean had still been hurt, which Cas had promised to protect him against. 'Dean, I'm sorry. I couldn't bear to see you with all those girls.'

'Cas, all you had to do was say and I'd have stopped,' Dean said softly.

'Would you have though? Would you have been able to do that?'

Dean paused. Cas had been expecting as much. 'It's fine, Dean. I know you.'

'Cas…' Dean moved forward to kiss him, probably, but Cas pulled back.

'Please don't do this to me again. I can't.'

Dean nodded. 'Okay.'

'I'm sorry my sigils didn't work,' Cas said.

'No worries,' Dean said. 'I deserved what I got. I hurt you, and I didn't protect Sammy. Something was bound to happen.'

'When did they stop working, do you know?'

Dean thought about it. 'Can't say for sure,' he replied eventually. 'About a month ago.'

'And your father's been hurting you since then?'

'No, Cas, it's fine-'

'No, Dean, it isn't, I should have been there to protect you, and-'

Dean leaned forward and kissed the angel, effectively shutting him up. 'It's fine, Cas,' he said once they broke off.

Cas felt tears forming in his eyes. 'Dean…'

'You have to go, right?'

'I'll be back soon,' Cas said before he disappeared from the Impala's passenger seat.