"So… it's always like this with you, isn't it?" Donna was watching the spot where Dean's friend Castiel had disappeared, shaking her head at the situation. She hadn't specified which of the men she was talking to, but they both seemed to think she was addressing them:

"Pretty much," Dean said.

"It seems to be the case," the Doctor said, rubbing his forehead with a distracted look on his face.

Dean and the Doctor both glanced at each other and smirked before Dean asked, "How you feeling?"

"Everything seems to be working," the Doctor assured him, even going so far as to move his arms and legs as if that was any kind of reassurance when the problem had been with his head. "Other than a lingering psychic headache from the feedback of your friend's telepathic touch, I think I'll live."

"What did he do, anyway?" Dean asked, offering the Doctor a hand up.

"Oh, the psychic equivalent of a good old-fashioned tune-up," the Doctor said easily. "One part starts acting up, the light flashes, and ding, Bob's your uncle, you've got an angel in your head with a telepathic screwdriver to see what the problem is."

"I don't think that explained anything at all," Dean said dryly.

Donna laughed. "He likes to think he's so clever by talking in circles."

"Oh, is that why he and Sammy get along so well?" Dean asked in mock surprise. Then, when the Doctor gave both of them a dry look and an "oy," Dean grinned over at him. "Seriously. What happened?"

"A meeting of the minds," the Doctor said. "Literally. Your friend and I met on the psychic plane, took stock of each other, and then he found where the problem was and erected shiny new barriers to contain whatever's in there." He tapped the side of his head. "I've had worse in there, believe you me."

"Why does this not surprise me," Donna said dryly. It seemed like every time the Doctor revealed something about himself, it was some new mystery or trauma. The guy needed about nine hundred years of therapy, in her opinion—but traveling time and space and saving people seemed to work just as well, so she wasn't going to complain.

"Actually," the Doctor said, looking toward Dean, "I learned a few interesting things about your angelic friend while we were sharing each other's thoughts."

Dean leaned forward, his eyes sparkling with interest. "Oh?"

Donna only barely kept back her delighted smile and the laugh that wanted to come with it. Better to let Dean figure this out on her own, she figured. Even if his interest—in more than just a professional sense—was written all over his face. "Spill, Doctor," she ordered.

The Doctor met Donna's gaze with only a whisper of the smirk that she expected from him—since she was fairly certain he could see the same obvious interest she could—and then looked back to Dean, perfectly serious. "You're welcome to join me and Donna," he said. "Let Heaven and Hell or whatever they want to call their respective dimensions fight their war some other way with some other vessel." He said that last word with revulsion, his features twisting. "Sam's welcome aboard too, you know."

Donna frowned, losing her good mood entirely. She should have known that Dean would find someone to interest him who was only interested in using him in return. She didn't have the whole story yet, but the way the Doctor said "vessel" had her already considering pounding Castiel the next time she saw him.

The truth was: she was more than a little protective of Dean—and had been ever since she'd met him when he was so young she was his babysitter. It seemed like every time she met him, he'd found some new way to get beaten down, and she was starting to get sick of it.

She was honestly worried that he was going to end up like the Doctor: full of a quiet rage that spilled out despite his best efforts. And since Donna didn't see Sam around, she knew she had to tell Dean the same thing she'd told the Doctor on too many occasions: "You don't need to be alone."

Both Dean and the Doctor turned to face Donna, and Donna quickly realized that she hadn't actually articulated her train of thought. She must have sounded like she was offering Dean reasons to stay aboard the TARDIS—though now that she thought of it, she wouldn't mind being there for him. She just wondered if she'd be able to keep up looking after two high-maintenance boys.

"I do alright," Dean assured her with a cocky, crooked smile. "Plus, I've usually got Sam around. I don't actually need a babysitter," he added, and she couldn't help but smirk at his teasing tone.

"Not what I was proposing," she shot back.

"Or propositioning?"

Donna laughed at the suggestive way Dean waggled his eyebrows—and then at the look of intense longsuffering on the Doctor's face. "Flirt!"

"Wasn't a no," Dean pointed out.

"Stop it," the Doctor said in a warning tone, but Dean's smile only grew.

"Heard that before."

"Then you'd think you'd be used to it."

"I am; you'd think you'd be used to it," Dean shot back without missing a beat.

"He's got you there," Donna agreed, not even bothering to hide her laughter. Every time she and the Doctor met up with Dean, she was further and further convinced that having him aboard the TARDIS would be the definition of fun. Not many people could keep up with the Doctor—she knew from experience—and it was always fun watching people take him down a peg. Or twenty.

The Doctor shook his head before he turned to Dean, meeting Dean's gaze so Dean could understand how serious he was. "I mean it. I'm sure the TARDIS can figure out how to avoid extradimensional beings bent on bringing Armageddon to your world. Should be simple enough for her, actually—and it could save you and your brother a lot of heartache."

Dean tipped his head to the side and narrowed his eyes, a sure sign that he was actually considering the Doctor's offer and not just confidently brushing it aside. Even Donna could see the intense concern in the Doctor's eyes, and he was looking at Dean, not her. That kind of care could get anyone thinking.

Still, even Donna could have predicted Dean's answer: "I can't go anywhere without Sam."

"I wouldn't expect anything less. The offer has always been for both of you to come with me," the Doctor said evenly. "Where is he?"

"We were on a hunt before Cas showed up and zapped me somewhere else to talk. He's doing some research—shouldn't take too long for me to find him again." Dean held up his cell phone. "You mind?"

"Not at all," the Doctor said, gesturing for Dean to do what he needed to do.

Donna watched Dean leave and waited for him to get into what looked like an animated conversation with Sam before she slid over to the Doctor, both eyebrows high on her head. "So… are you going to tell me what's going on or not, Space Man?"

The Doctor pressed his lips together, let out his breath, and then nodded once, sharply. "Castiel and the other angels are trying to convince Dean to let them use his body so they can fill it with their leader and fight a war between Heaven and Hell. Sam is being recruited for the other side. It's an invasion in every sense of the word—privacy, autonomy, you name it. And they're trying to dress it up like it's all inevitable and the boys should just let it happen."

Donna pulled a horrible face. "You're right," she said. "Let's kidnap them."

The Doctor laughed outright. "Oh, is that what we're doing?"

"Isn't it?"

The Doctor laughed again and then gestured with one hand toward Dean. "Let's just see what he says, shall we?"