The marble altar was freezing, even though the sun was beating down fiercely. Donna could already feel her nose peeling and she hated the 'Rudolph with dandruff' look.
"Doctor, you promised me a holiday," she said. "Sun, sea, sand and margaritas. I see the sun and the sand, but where's the rest?"
The Doctor looked up from where he was crouched next to the altar examining the base with a large magnifying glass. "Sitting around all day on a beach with a trashy novel? You really wanted that?"
"Yes!" Donna said. "That's exactly what I wanted. Nobody shooting at us, nobody dying, just a trashy novel and a beach."
"That's rather..."
"Yes?"
The Doctor shrugged. "Dull."
"Not dull," Donna said. "Relaxing. With an emphasis on nobody shooting at us for at least twenty-four hours."
"Think of this as a diversion, then," the Doctor said. "I think I know just the place. But we need to investigate this a little first."
"Doctor, why is an altar in the middle of nowhere interesting?" Donna asked, a little wearily and not at all angrily.
"Because it's an altar that's emitting a distress signal," the Doctor said. "Most unusual, that."
Despite herself, Donna was intrigued. She always tried to resist the Doctor's little tangents because they usually ended up with slime, lasers or on special days both, yet she never seemed to succeed. She missed the days when curiosity was a foreign word and nothing weird ever happened.
"What do you think it is?" Donna asked, edging nearer to the altar.
"Haven't the faintest," the Doctor said happily. "That's why it's a mystery."
He pocketed the magnifying glass and began scrabbling at the base, shifting a bit of sand out of the way to reveal more black marble.
"I think we'll need some shovels," he said and then glanced up. "You might want some suntan lotion as well."
***
It turned out that the TARDIS was remarkably well stocked with suntan lotion and remarkably poorly stocked with shovels. The Doctor huffed and insisted that there must be more than one lurking around but a careful search of the rooms nearest to the console room revealed no more.
"I suppose we could take it in turns," the Doctor began hopefully.
Donna gave him her best glare and he subsided slightly.
"Maybe not," he conceded.
"He who finds the altar, digs out the altar," Donna said, carefully rubbing lotion into her tender nose.
The Doctor hoisted the shovel onto his shoulder and marched towards the door of the TARDIS. "I think there's a red parasol thing in the wardrobe if you need it."
By the time Donna had retrieved the parasol, a large towel and put a few bottles of water in a cold box, the Doctor was standing in a hole a couple of feet deep, digging industriously. Donna settled on the towel with the parasol position against the sun. Watching the Doctor digging and doing some actual work for a change instead of letting him swan in at the last moment with a brilliant solution was rather fun. Even when he balled up his jacket and threw it at her, hitting her right in the face, Donna felt happy and cheerful about the whole thing. It was almost like a holiday without the flies and smell of overheated ice cream.
The hole grew deeper, first to the Doctor's waist and then to his chest. Eventually it became too deep to shovel effectively without proper reinforcements to the sides and some kind of bucket-on-pulley system for extracting the sand so the Doctor climbed out of the hole and looked at it for a while.
"Find anything?" Donna asked.
He hummed a little, scratched his head and said, "Well, no. Not really."
"Oh." Donna looked at the hole, too. "How far down do you think the altar goes?"
"If I had to guess, I'd say that it might go all the way to the bedrock."
"And if you didn't have to guess?" Donna asked, waving the sonic screwdriver that she had extracted from the pocket of his sweaty jacket.
The Doctor looked thoughtful for a moment, watching the sonic screwdriver gesture and circle. After all these weeks Donna still found it odd that a man with so much energy could be completely still sometimes, motionless and blank as though all that energy and brilliance was working in some other dimension that left his body behind for a while.
"Donna," the Doctor said slowly. "You are a genius. Be right back, don't worry."
Donna didn't start to worry until he closed the doors of the TARDIS and the grinding sound of the engine began. Then she worried a lot and started running towards the blue box, but it was too late and the sand was too difficult to run through and the TARDIS dematerialized long before she reached it. Never during their travels had Donna imagined that the Doctor would abandon her. She knew when she left with him that it wasn't a safe life or a predictable life, but she had trusted that the Doctor would always try to find a way for them and he would never leave anyone behind. As she stared at the square of flattened sand, Donna shivered in the heat and felt terribly cold and alone.
She trudged back to her towel on the sand and, for lack of anything else to do, took a water bottle out of the cold box and began drinking. It occurred to her after a minute that she should probably conserve her water because there had been no sign of anything other than sand and heat since they arrived, but Donna had given up long-term planning when she gave up the dream of being married to Lance. The Doctor would either come back or not and a few bottles of water weren't going to make much of a difference if he never returned. Despite that thought, Donna did not open a second bottle of water.
It felt like she had been sitting there forever when she finally heard the TARDIS engines again. According to her watch, the Doctor had only been gone for an hour and Donna felt too happy to see the familiar battered police box shimmering into existence next to the altar to build up much anger towards him.
"Sorry," the Doctor said when he leaned out of the door. "It's much harder to make short hops than, say, travel fifty centuries and across three galaxies. A little ironic, that."
Before Donna could say anything he disappeared into the TARDIS and reappeared a moment later trailing several long cables that pulsed and glowed faintly under the glaring sun.
"Why did you need to make a short hop?" Donna asked.
The Doctor waved his cables. "Needed to bring the TARDIS closer to the altar. If we hook up the TARDIS to the altar, we might be able to get a bit more information out of the distress call and that might tell us why an alter fused to the bedrock is sending a distress signal out in the first place."
"You didn't think of this before you dug a great big hole in the sand?" Donna asked very, very calmly.
The Doctor shrugged and knelt by the altar. Donna had learned over the weeks that if the Doctor avoided answering a question it was usually because he knew the answer and the answer would make him look silly. No matter their species, it seemed that some things were universal to men.
"Right, into the TARDIS," the Doctor said after a minute, springing up with the shovel in hand and hurrying over to Donna.
His hand was warm and dry despite the heat and if Donna pulled a little heavily on him when he helped her up so that he nearly overbalanced, it was only what he deserved after all. She gathered up the towel, parasol and cold box and followed the Doctor to the TARDIS. The cool air of the control room made Donna shiver and the Doctor's jacket felt nice when he wrapped it around her shoulders even though it was sweaty and sandy. She let him rush around the console without interfering - they had already established that she was only to touch what he told her to touch - and told herself that she had never been worried that he would leave her on the dead planet. It just wasn't what the Doctor did.
"Got it!" the Doctor declared and a moment later the air beside him fuzzed, fizzled and then resolved into an image.
The being was slightly shorter than Donna, slim and pale with white hair that seemed to wave gently in a breeze that nobody else could feel. It wore long, pale green robes and its features were delicately androgynous. The almost human appearance made it seem at once familiar and far more alien than some of the bizarre creatures that Donna had met in her travels. She could see the outline of the control room through the creature and she could not decide whether it was the TARDIS that made the alien look so pale or whether that was its own colouring.
"Greetings," the alien said, and the way that it focused on something just over Donna's shoulder told her that it was some sort of recording. "We are the second colony of the Arashkan Republic. This world is now beginning an ice age and requests for help from the home world have not been acknowledged. We have taken the decision to put our colony into suspended animation beneath the surface until the ice passes or home world sends aid. If you are receiving this message then the systems to wake us have malfunctioned or failed to respond at the appropriate time. Please help us."
The Arashkan flickered and disappeared and for a long moment Donna stared at the place where it had stood.
"Doctor," she said eventually. "It's a desert out there. When did the ice age end?"
The Doctor seemed to shake himself and dart around the console, flicking switches as he went.
Then he stopped with a sad look on his face and said, "Around five hundred thousand years ago."
"Is there any chance that they could be woken up?" Donna asked in a small voice. She wanted to shout and protest that it was all wrong but this just seemed too big for her. "Doctor?"
Pain and age showed in his eyes and for a moment all the years seemed to weigh him down, as they never normally did.
"No," the Doctor said. "Their life-signs are gone. There is just enough power to send out the distress call and that will probably run out in another few centuries. The only thing left is the altar, which was once a transmitter until the sand built up on this world."
"Isn't there anything we can do?" Donna asked. "This is a time machine. Can't we go back and wake them up when they should have woken up?"
"Time isn't like that," the Doctor said. "She lets you push her and bend her a little, but she doesn't forgive if you go too far. This little planet died half a million years ago and that fact is fixed."
"What's the good in having a time machine if you can't change anything?"
"We can be witnesses," the Doctor said. "Nobody knew this colony's fate until we arrived here. Now we know."
"That's not enough," Donna said. "How can that be enough?"
"Sometimes it has to be enough," the Doctor said. "We can change so much, Donna, but if we could do anything we wanted then we would be truly dangerous."
Donna never used to be a big picture girl. She saw what was around her and did something, or not, and didn't worry much about things like consequences beyond her little sphere. It was easy to see why traveling with the Doctor could be addictive and she thought that she had known why so many people chose to travel with him despite the dangers. She wondered how many of them had seen this side of his life where all he could do is watch and be a witness, not interfering even though everything in him must be crying out to save the people.
She did not notice that the Doctor had left the TARDIS until he closed the door, winding up the cables as he walked back to the console.
"Are you all right?" he asked.
Donna sniffed and put on a smile. "Yeah, yeah, of course I am."
"Do you still want that holiday?" the Doctor asked quietly.
Donna shrugged. "Maybe later."
The Doctor accepted that without asking any questions and began walking around the console flicking switches and turning dials, except he walked a little more slowly than usual and there was a little less energy trying to escape from him.
"So, where do you want to go?" he asked.
"Somewhere with lots of people," Donna said. "And no sand."
The Doctor grinned. "I think I know just the place."