"Cas, help!" Dean grunted as he hefted the man he and Sam were carrying onto the pitted wooden table.
Castiel backed away, eyes wide in what Dean might have taken for fear. "Get that man out of here NOW."
"Why?" asked Sam. "Who is he?"
The man gasped and sat up. His eyes fell on Castiel. "Oh, hello, Castiel," he said in a British accent. "You've got a new hair cut." His smile slipped. "I don't like it."
"It's a new vessel, Doctor," said Castiel grudgingly. Dean and Sam stared at them.
"Oh," said the Doctor, nodding so his poofy bangs flopped back and forth. "That would explain it."
Castiel turned to Sam and Dean. "Where did you find him?"
"Wanderin' down the highway," said Dean. "He said your name 'bout a dozen times and then collapsed."
Castiel turned his piercing blue eyes upon the Doctor. "You need to leave. Now." He walked away from them, over to the wall.
The Doctor vaulted off the table and stood a few feet behind him. "I came for you, Castiel. I heard your message."
"My message!" Castiel snarled, whirling about. "I prayed for you twenty years ago! When Mary needed-" he broke off with a cautious look at Sam and Dean, who were suddenly showing much more interest in the conversation.
"What about our mom?" Sam asked.
The Doctor sighed sadly. "Time vortex. It muddles timelines. But you know that, don't you."
"I know what you have told me," said Castiel stiffly. "I do not need to take your word for it."
"For a man of faith, you're distressingly cynical," said the Doctor.
"Be that as it may, you need to leave now."
The Doctor bounced on the balls of his feet. "Well, that's the problem, isn't it. You see, I'd really love to, but I can't just now. My TARDIS is malfunctioning." He grinned in a boyish fashion. "You're stuck with me, Mr. Angel." He spun about again and hopped on the table, crossing his legs. "I met an angel while I was away. Well, hundreds of angels actually. There was one called Angel Bob. Poor fellow."
"Uh, Cas," said Dean. "Who the hell is this guy?"
Without taking his eyes off the Doctor, Castiel said, "An old…friend. If that is what he can be called."
"An old friend from when?" asked Dean. "Before you raised me from Hell, I thought you had stayed in Heaven."
"He is from the last time I walked the Earth," said Castiel. "The year before the first year of the Lord."
"Yes," the Doctor piped up. "There was an awkward matter of an unexpected pregnancy. Partly my fault," he sucked air through his teeth, "sorry."
Castiel rolled his eyes.
Distinctly not amused, Sam looked at Castiel and asked, "What did you mean you prayed to him about our mom?"
That wiped the silly expression off the Doctor's face. He suddenly looked much older, and his eyes had become sad and empty. "It seems I can never apologize enough."
The Doctor smiled a tiny smile up at the two boys. He barely came up to Sam's nose, and yet Sam felt again as though he were eight years old, looking up at the adults who were the masters of his fate. "The Winchester Boys. Oh, they tales they'll tell about you two. I never thought I'd see you again."
"Again?" said Dean.
When the Doctor next spoke, it was to Castiel. "I heard your prayers, Castiel, and I came for Mary. I told her the truth, perhaps more than I should have. She understood. She was very brave."
"They're always brave," said Castiel.
"Mary Winchester's death was a fixed point in time," the Doctor continued. "No matter how desperately I tried to change it. I tried to take her away, I jumped her forward in time. But we always came back to the nursery." His eyes fell upon Sam. "She made her decision, in the end. And I'm sorry."
The three pairs of eyes which watched him ranged in emotion from pity, to shame, to sheer rage.
"You mean," said Dean through clenched teeth, "that you could have saved our mom?"
"No," said the Doctor. "I knew even before I tried that I would fail."
"That isn't what matters," said Mary gently, pressing her hand to the Doctor's cheek. "What matters is you tried." She looked away across the clearing, where John, eight-year-old Dean and four-year-old Sam were clustered around the campfire, sharpening their blades while hotdogs roasted over the flames. "What matters is that I know they're still alive."
"What's the point of having a time machine if I can't save the people I love?" asked the Doctor.
Mary only smiled, and stepped back inside the TARDIS. "It's time, my friend. You have to take me home."
"Just one thing first!" the Doctor cried, much more lively. He bounded up to the console and threw a lever. "I'm taking you to the Forest of Nyamh. It's beautiful this time of year. They have flowers that glow in the dark! Oh, you'll love it, Mary, it's-"
Mary laid a gentle hand on his arm. and smiled up at him, but her eyes were full of tears. "Thank you, Doctor. For everything."
"Please," said the Doctor when they landed in the Winchesters' front yard. "Is there nothing I can do?"
"You've done so much already." She stared up the path. At the door, though, she turned back to find him still watching her. "There is one thing."
Mary gestured toward the house. "Watch out for them. Please."
The Doctor nodded. "Always."
Dean and Sam still glared suspiciously at him, but the Doctor had felt Castiel in his mind, and knew the angel understood. And that the Winchesters never would.
"I heard your prayer, Castiel," said the Doctor. "I did all I could."
"Oh my God…" said Dean, realization dawning across his unshaven face. "You're not…God?"
The Doctor laughed. "No. No, I'm not God. He and I don't get on."