“Listen,” said the Doctor, “I really don't think this is a good idea.”

The man with the very-sharp-looking knife didn't respond beyond striking a dramatic about-to-stab-someone pose.

“I have nothing against religion,” the Doctor continued, “but human — or it this case Time Lord — sacrifice is just not on.” He tugged at the chains holding him to the altar. They were strong, robust chains made by someone who took pride in their workmanship. “For one thing it's messy and -”

He was cut off by a chariot crashing into his would-be murderer. He twisted as well as he could to see what was happening. It was a welcome but unexpected interruption.

Donna adjusted her winged helmet, climbed down from the chariot, and said, “I hope you're grateful.”

“Donna, you're.. you're... a soprano?”

“You'll be a soprano in a minute if you don't stop staring at my breastplate.”

The Doctor dragged his eyes upwards. “Sorry, it's just... where did you get that outfit?”

“In the TARDIS.”

The Doctor was fairly certain that he'd never seen it before in his life. He'd remember, he was sure he'd remember. How could he forget a Valkyrie outfit with a Donna-sized breastplate?

“I'm exploiting their whatsit,” said Donna. “Mythology.” She looked around at the cowering bystanders. “I'm taking you to Valhalla,” she said loudly. “That's like Heaven,” she added more quietly for the Doctor's benefit. She examined the shackles that held him. “Have you got a key for these?”

“Would I still be lying here if I had a key?” asked the Doctor.

Donna shrugged. “I suppose not.”

“You'll have to use the sonic screwdriver,” he said. “It's in my jacket.”

Donna reached into his pocket and retrieved the device. “How do I work it? Where are all the buttons?”

“Just sort of point it and hope,” said the Doctor. Then he said “Ow! Point it at the metal bits, not my skin!”

“Sorry,” said Donna. “Anyway,” she said conversationally as she worked, “how did you manage to convince them you were a virgin?”

“What?”

“They only sacrifice virgins,” said Donna, who had done some research while strapping on her armour in the TARDIS.

The Doctor tried to sit up to protest, but he was still chained to an altar so he couldn't. “I'm not a virgin!”

“I guessed that much,” said Donna. “I assume you must have been hot in some previous regeneration or other.”

“You don't think I'm hot now?” he asked, feeling somewhat insulted.

Donna looked at him critically. “Not so much.” She looked around. The scattered onlookers were starting to move closer again. “I think they're onto us,” she told the Doctor.

“Sing,” he told her.

“What?”

“Sing! You're a Valkyrie, that's what Valkyries do!”

Donna nodded and turned to her audience. “Stop!” she cried, “In the name of love!” She almost had his left foot free, she just needed a few more minutes. “I am taking him to Heaven,” she sang, somewhat tunelessly, “Which is a little bit like Devon.”

“Donna...”

“And I doubt he is pure, I am fairly sure. There was Rose and then Martha, and he's mentioned a horse called Arthur.”

“Donna, I did not have sex with that horse!”

“Shut up,” she said kindly. “Martha told me that he's a bit gay, he's probably had his end away.”

“Could you sing about another topic?” asked the Doctor rather desperately.

“And there's River at some point in time, I can only assume that love is blind. He is made of elbow and knee, he does not appeal to me.” She handed him the sonic screwdriver as she freed his right arm. She was getting quite into the singing. “I expect if you shagged him he'd start to cry, and look at his nose and that lazy eye.”

The Doctor grabbed her by the arm as he freed himself. “You can stop now, really.”

“Are you sure? I think they like me. Maybe I should sign some autographs?”

“We're going to Valhalla,” he said firmly, helping her up into the chariot.

“That had better not be a euphemism,” she said.

“It's not, you've articulated your non-attraction to me quite eloquently. Where did you learn to drive a chariot?” he added.

“I didn't.”

“I'll drive,” he said, taking the reins from her hands.

“Please yourself.”

They sped off towards freedom and the TARDIS. Donna grabbed hold of the Doctor in case she fell off the chariot, quite secure in the knowledge that she didn't find him in any way attractive. When they arrived safely she freed the horse and waved it off.

“That was quite a good rescue,” she said, pleased with her work.

The Doctor opened the door and trudged inside without replying. Donna glared at his back and mouth something rude about his parentage.

“I don't think you get to be annoyed when I saved your life,” she said.

“You didn't have to sing about my sex life!” he cried. “Those people probably think I had sex with a horse!”

“But on the other hand, you're not dead.”

“I'd have regenerated,” he insisted.

“Might not have,” said Donna reasonably. “And you're welcome.” She headed to her room to change out of the ridiculous outfit. She paused at the door to the rest of the ship. “Next time,” she said, “don't tell them you're a virgin.”

“I didn't!”

“Okay, then try not to look like one. Were you wearing your glasses? Because no offence but they make you look like someone who collects comic books and action figures.”

“They're graphic novels,” he protested wearily.

“You keep telling yourself that.” Donna left the console room with her head held high.

“Thanks, Donna,” he said when he was certain she was out of earshot. Then he stroked the console a bit to cheer himself up.