The Doctor and Adric had reached the river quickly, walking at a brisk pace. Adric was energetic and alert; the only remnants of the difficult night he had passed were a slight puffiness and darkness around his eyes.
They paused at the river to look about, calling Nyssa's name in all directions.
"This way," the Doctor said with a tilt of his head when it was clear that their companion had not heard their cries.
Adric glanced back at the water. "Did you ever ask Gerran about the irrigation system?"
"No, I never got around to it."
"I suppose it's really fairly simple, but it wouldn't be possible without the plastic pipes."
"Yes. Plastic is certainly an effective material."
"But it's not used much on spaceships, is it?"
"Not in the engine components, of course, but it's often found in the plumbing systems."
"The ship their ancestors arrived in must have had a lot of plumbing, then. There are at least two kilometers of irrigation piping."
The Doctor appeared contemplative for a few minutes, merely nodding absently at Adric's continued comments. Finally he said, "I wonder where their ship crashed?"
Adric replied, "I don't know. I haven't seen any wreckage. Have you?"
"No, not a bit. Of course it could be some distance from the village—"
"But not too far. Gerran said the glass came from their ship. They probably wouldn't have carried it all that far."
They reached the area where Vuir collected herbs and searched about for Nyssa for some time, but they found no sign of her. As they headed back toward the village, the Doctor suggested a slight detour over one of the tallest batholiths in the vicinity.
"It's going to be a bit of a hike. Can you manage?" he asked.
"Of course," Adric sniffed. "I told you I'm fine."
The Doctor led Adric up the rocky slope. The boy scrabbled along behind, trying to keep up, but after a short time he was clearly winded. He was beginning to squint in the late morning sun, too.
"Just wait there for a few minutes. I'll be back soon," the Doctor said, clambering easily to the summit.
Adric wanted to follow, but his eyes had begun to water, blurring his vision slightly. When his foot slipped and he slid several meters down on the rough rocks he gave up, sitting down to rub at his palm, which he had scraped badly in the fall.
The Doctor returned in about ten minutes. "Are you all right?" he asked when he saw the boy's position.
Adric shrugged and turned his hand over, trying to hide his injury and the accompanying frustration. "Just waiting for you."
"We can rest here for a few minutes longer if you like—"
"No," Adric replied quickly, "I'm fine." He began to stand, but he needed to brace himself with his hands, and he winced when his sore palm pressed against the rock.
The Doctor lowered himself to a relatively flat rock and sat with outstretched legs. "The view is rather spectacular from here," he commented with a surreptitious sideways glance at his companion.
Adric joined him on the rock, easing his body down beside the Time Lord. "I suppose it was even better from the top."
"Yes, I could see the entire area."
His eyes moved from the vista to Adric's hand. "How badly did you cut it?"
"It's fine—"
"Adric, just answer the question—honestly." He grasped Adric's wrist and turned over his hand to expose the palm.
"It wasn't very deep."
"It's nearly healed now."
"I know. I told you it was fine."
"Yes, you did." He looked out over the land again.
Adric's voice was soft when a moment later he said, "I still heal the same."
The Doctor did not respond to this. Instead he said, "I saw no signs of the crash site."
"Really? Nothing? But surely there'd be some large pieces of metal still. They wouldn't have deteriorated completely, would they?"
"You tell me. What is the average rate of decay for transition metals?"
"What?"
"The rate of decay, Adric. This is precisely the type of situation in which you use the formulae you were studying just before we arrived here."
Adric frowned. "The formulae? For rate of decay?"
"From the text—the one you had misinterpreted."
Adric shook his head. "Doctor, I don't know what you're talking about."
The Doctor's eyes were fixed on him now. "Do you remember arriving here?"
"Of course! We stepped out of the TARDIS and Tegan was mad because we weren't at Heathrow—"
"And just before that?"
"You said you wanted to come here because it was odd that there was humanoid life here; there hadn't been three hundred years ago."
"If the cosine of theta is the square root of three over two, what is theta?"
Adric scoffed. "Thirty degrees, of course!"
"And what is the integral of three x-squared evaluated from one to three?"
"Really, Doctor, that's ridiculous! It's twenty-six, of course."
"But you don't recall our discussion about the ionic value of tamallium?"
"No."
The Doctor stood, extending his hand to Adric. "Come on. We're going back to the village."
Waving the hand aside, Adric rose, asking, "But what about Nyssa?"
"Perhaps Tegan and Gerran found her. Anyway, she's not out here."
As they climbed down the batholith, Adric noticed the Doctor watching him almost constantly. Finally he said, "I told you I'm fine!"
"I want you to try to remember something."
"What?"
"Forty-six, nougat, fusion, twelve, Ios, silicon."
"Why would I want to remember that?"
"Just try."
"Fine. But I wish you hadn't said 'nougat.' It's making me hungry."
------
Morra's ebullient ramblings almost succeeded in loosening the knot in Tegan's stomach. She was still concerned about Nyssa, but the little girl's perpetual cheer was infectious. After she had searched around the area where the child had easily led her, she permitted Morra to show her the flowers.
"But we don't have very much time. I have to get back to the village and let the Doctor know that Nyssa isn't here," Tegan cautioned.
Morra took Tegan's hand again and urged her toward several low-growing bushes.
"The flowers are down here," Morra said, already falling to her hands and knees to look near the bottom of the plants.
Tegan crouched down. Flowers resembling wild roses grew in small clusters amid the dark green leaves. Morra had already begun plucking blossoms and dropping them into her skirt. "I'm going to make you a crown," she announced.
"We really need to get back," Tegan began.
"Please? It's going to be so pretty on your hair." Morra's small hands moved quickly; she had already begun twisting the stems together.
"Well, maybe just a tiara."
"What's that?"
"It's like a crown, but it just covers the front of your head."
Morra smiled. "Okay! Princess Tegan gets a tiara!"
Tegan sat quietly for several minutes until Morra had finished her creation. With a proud grin she placed the arc of flowers on top of Tegan's head.
"Oh! You look beautiful!" Morra gasped.
"Thank you. But we need to go now." Tegan shifted her legs around so that she could stand. Her thoughts had quickly returned to Nyssa as she waited for Morra. She had been staring at her hands, noticing the small cuts and scrapes that remained from the rockslide. What if Nyssa had been involved in a similar accident?
Morra reached for the garland. "Just a little longer, please?"
Tegan shook her head. "No, Morra. I really have to get back—"
The child pressed her hands against Tegan's forehead as she began to rise. The Australian seemed to draw in a sharp breath, then she sank back down to the ground. Morra knelt in front of her, moving her small hands down to Tegan's temples, holding her head steadily. The girl's happy expression, however, quickly changed. After a minute her hands dropped to her sides.
Tegan blinked in confusion. Morra stood before her crying. A moment ago the child had been laughing and smiling. Tegan felt as though she had missed something, but she had no idea what.
"Morra?" she said. "What's the matter?"
The girl continued sobbing. "I'm scared," she gasped. "I want my momma."
Tegan stood quickly, forcing a small threat of vertigo away with a shake of her head. She took Morra's hand. "Come on, then. Let's get back."
The walk to Cira's house was short, less than ten minutes, but Morra continued to cry. Tegan's comforting words had little effect on the disconsolate child. As soon as the house came into view, Morra ran for the door, opening it and disappearing inside. Tegan followed perhaps twenty seconds behind her.
When she stepped through the doorway she found Cira kneeling before her daughter, hands resting on her head. "Sshh," she soothed. "It's all gone now. Momma's going to give you something pretty to see instead."
Morra's eyes were still teary, but she appeared less upset. As Tegan watched, Cira closed her eyes for a few seconds, and Morra's expression abruptly changed to one of joy. Mother and daughter both opened their eyes.
"It's all right, love," Cira said, giving the child a hug.
Morra looked up at Tegan. "You lost your crown!"
Cira turned, surprised to see Tegan standing inside the doorway. Before she could speak, however, Tegan said, "I'm sorry. I don't know what happened. She just started crying and I—"
"It's all right," Cira said rather shortly. "She was just tired. She needs to rest now. Please excuse us."
Tegan immediately backed out the door, interpreting Cira's cool tone as one of reproach. She still did not understand what had caused the child's distress, but it was clear that Tegan was the object of blame.
Tegan hurried back toward Gerran's house. Adric and the Doctor were approaching from the opposite direction. They were alone; they had not found Nyssa.
"No luck?" asked Adric when they neared each other.
Tegan shook her head. "No."
"Perhaps Ellea has heard something," the Doctor said. He ushered his companions toward the house.
Tegan reached the door first and grasped the handle. She glanced down at her hand, lifting it to study the scrapes. She prodded one of the deeper ones.
"Is something the matter?" the Doctor asked.
She looked up at him. "I was just wondering when I scratched my hand."
"Tegan, that's not very amusing," he remonstrated. "You could have been seriously hurt."
"What are you talking about?"
Adric stepped forward. "The rockslide, Tegan."
She blinked at him. "Rockslide? You mean out there?" She turned to point at the batholith. "Where I saw the bird?"
The Doctor took her shoulders. "Stop this, Tegan. It's not funny."
"I'm not trying to be funny! I—" She sniffed; something was tickling her upper lip. She reached up to rub a finger across it. She was surprised to feel warm liquid.
"Oh Tegan, not you too." The Doctor was staring at her in grim fascination.
She lowered her hand to examine her finger. "Cripes, it's blood."
The Doctor quickly retrieved yet another handkerchief from his pocket and offered it to her. She took it and pressed it to her nose as he led her inside and urged her to sit in the nearest chair. She had already tilted her head back.
"I'll get a cloth from the kitchen," Adric offered.
"This is the first nosebleed you've had here?" the Doctor asked Tegan.
She nodded and replied rather nasally, "First one ever."
Adric returned with a damp towel and held it out to Tegan. She lowered the handkerchief tentatively.
"No," the Doctor said quickly, "put it back."
She had only caught a glimpse of the cloth, but she saw that it was saturated with blood. Her hand shook as she lifted it toward her nose again. The Doctor rested a hand on her shoulder then turned toward Adric. "What were those things I asked you to remember?"
"Forty-six, nougat, fusion, twelve, Ios, silicon," Adric replied immediately. "But I still don't know what the point of that was."
"A simple memory test," he said with a dismissive wave of his hand. "It seems your short-term storage and retrieval are not impaired."
"But Tegan's is."
Tegan looked at the Time Lord with wide, frightened eyes. He lowered her hand again to check the handkerchief then offered her the towel. She wiped it over her nose and upper lip.
"What's going on?" she asked.
"I'm not sure, but I'm beginning to have an idea," replied the Doctor. He pulled the small torch from his pocket and shone the beam into each of her eyes. She squinted at the brightness but did not turn her head away.
"Same pupil dilation," he murmured, "and mild light sensitivity."
"Her nosebleed lasted longer," Adric pointed out.
"Yes, it did," the Time Lord confirmed.
"Doctor? What's happening?" Tegan asked.
"You were with Gerran before returning here?" he inquired.
"No, Morra took me out to the area just outside the village. Gerran said he needed to speak with Cira, and Morra really wanted to go—"
"Did she? And what did you do with her there?"
"We looked around, called for Nyssa. Then she wanted to show me some flowers, and after that we came back here."
"That's all?"
"Yes." Tegan dabbed at her nose again. "She started to cry, so I took her home."
"What caused that?"
"I have no idea. I was just sitting there, and she put a garland on my head, and then she began to cry. She wouldn't tell me why."
"Where is the garland now?"
Tegan reached up. "I suppose it fell off. I don't remember."
"And after you returned Morra to her home, what happened?"
Tegan shrugged. "She ran inside. I followed to be sure she was all right. Cira must have comforted her because she was fine by the time I got in the house. But I think Cira thought I'd done something to Morra. She seemed sort of upset with me, so I left."
"And you came straight back here?"
Tegan nodded.
"How do you feel now?"
"Fine."
"All right. We need to find Nyssa as soon as possible then return to the TARDIS. But we must stay together at all times. I don't want either one of you to leave my sight."
"Why?" Adric asked.
"Because," the Doctor replied, "someone or something here has affected both of you in the same way."
"So you think I'm sick just as Adric was?"
"Sick? No. I don't believe this is an illness. I believe it is the effect of a specific action—one that has caused a brief yet very significant disruption of the electrical activity in your brains, leading to memory loss as well as the other symptoms we've seen."
"What sort of action?" Tegan asked.
The Doctor shook his head. "I'm not sure."
"Do you think it has something to do with Nyssa's disappearance?" asked Adric.
"Possibly." The Doctor was already moving back to the door as he spoke. "But regardless, we need to find her. Come on."
------
Nyssa had found that remaining still was the best way to keep her captor quiet and calm. He had finally settled down a few feet away from her, his back toward the cave entrance. He was hunched upon the ground with his legs drawn up to his chest and his head pressed against his knees. He still moaned occasionally, and she continued to believe that he was in pain. His actions toward her, she now realized, were not intended to harm her; rather, they were reactions to physical discomfort. However, this new understanding did not assuage her fear. Like a wounded animal, she knew that he could be extremely dangerous if provoked in any way.
Nyssa wanted to help him, to ease his pain. But to do this she would need to escape from the cave, and his current position blocked the narrow passageway quite solidly. She felt certain that he would not permit her to touch him again, and without the chance to examine him she had no way to determine what was causing his distress.
She watched him as he hunkered miserably before her. It was chilly and damp in the cave, and she wondered if he was cold. His clothes were in tatters, providing scant protection from the cold. The quilt lay at her feet. She ran her hand over the fabric, again noting the design and wondering where she had seen it before. Tentatively she lifted the edge of the quilt. The man did not stir.
Nyssa slowly slid the covering across the floor toward him. When it touched his fingers he opened his eyes to squint at it then lifted his head toward her. He grunted.
"Take it, please," she said softly. "You're cold. It will warm you." She gestured toward the comforter.
He grasped it and pulled it up then shrugged it over his bent shoulders. He coughed hoarsely and fumbled about with clumsy hands, reaching to the sides and front as though searching for something. Nyssa looked around. A jug sat against the wall just to her left. She took it and held it out to him.
"Is this what you want?"
He reached out, but his hands were still several inches from the jug. Nyssa got up on her knees and leaned toward him. "Here."
He moved his hands slowly until his fingers brushed against the jug, then he took it in both hands and drank. His motions were awkward, and water dribbled down his chin and onto his chest. She realized that all of his movements were jerky, and his actions in taking the jug showed her that his eyesight was very poor. Perhaps he was ill.
"What are you doing out here all alone?" she asked gently, although she did not expect him to answer.
He set the jug on the ground with a thud; it seemed to slip from his hand as he lowered it. Nyssa studied the container for a few moments. It was the same as the others she had seen in the village. As her eyes moved around the cave, she noted again that several baskets and additional jugs sat along the walls. She saw that the basket nearest her still contained something. Slowly she reached for it, wrapping her fingers around a slightly soft object with a rough outer covering. She realized that it was a cooked sweet potato.
"You stay here by yourself, but someone brings you food and blankets," she mused softly. "Surely you don't like living out here like this? Was this your choice?"
He moaned again, her words incomprehensible to him but her tone touching some small part of his mind that still remained unscarred.
------
As soon as the Doctor, Adric, and Tegan left the house they realized that the village was largely deserted.
"Perhaps they're all inside eating lunch," Tegan suggested.
A few quick peeks through nearby windows dismissed this theory.
"We should check all of the houses just the same," the Doctor said. "Nyssa could be inside any one of them."
They moved along swiftly, looking inside each home they passed. All were empty. When they neared the meeting house, they heard a low murmur of voices. Adric hurried up to the window through which he had looked two days before and peered inside. He saw the villagers gathered along the benches. Gerran stood at the front of the assembly addressing them, gesticulating excitedly as he spoke. Adric found his expression earnest and intense.
"They're having some sort of meeting, I think," he reported to his companions.
"Good," said the Doctor. "We can carry on looking for Nyssa here."
They continued their impromptu search with the same disappointing results. After half an hour the only buildings they had not inspected were the foundry, the store, and one additional, large edifice at the edge of the village. Nyssa was not at the foundry or in the store, and when Adric pulled the handle on the door of the final building he was surprised to find that it was locked. No other door had been barred or secured in any way.
"I think it's locked," he said, jiggling the handle.
"They said they don't lock their doors. Remember, Gerran didn't even know what a key was," the Doctor reminded him. The Time Lord walked around the building quickly, looking for any other doors or windows, but the front portal was the only entrance.
Tegan knocked on the door, calling, "Nyssa! Are you in there?"
The Doctor tried the door handle again, finding it just as unyielding as Adric had. "We'll have to force the door," he said. "Adric, give me a hand."
Adric nudged the Doctor aside and bent to study the handle more closely. He seemed to fiddle with it for a few seconds then he stood and, with a flick of the handle, opened the door. Grinning, he said, "Was that handy enough?"
"Nyssa!" Tegan called again, pushing past Adric to enter the building.
The interior was dim, but light streaming in through the door provided sufficient illumination for the visitors to see that a large table sat in the center of the room covered in a variety of objects. The Doctor inspected several, commenting, "A barometer—the decorative type from late-twentieth century Earth; a broken hand-held data storage device; an old portable DVD player—"
"What's a DVD?" interrupted Tegan.
The Doctor did not reply. He had moved on to a dozen or so papers spread out on the table. He skimmed the writing that covered them.
"What does it say?" asked Adric.
"It seems that someone has been making rather detailed notes about the things we've told these people. Nearly every bit of information from our second day here when we told them about Earth is recorded here."
Tegan and Adric read over a few of the notes. "Wow, talk about good memory!" she said. "They really have written down every detail. I don't even remember telling them all of these things."
Adric's hand was pressed over the edge of a single sheet, and his eyes were fixed upon it. "Doctor," he said slowly, "what's this?"
The Doctor moved over to study the page. "It's the formulae for rate of decay—"
"That you were asking me about earlier?"
The Doctor nodded.
"How—how did they know about this? They haven't shown any advanced mathematics knowledge."
"No," confirmed the Doctor, "they haven't. And this is something that you knew and understood three days ago."
Adric continued to stare at the lines of symbols until the Doctor touched his shoulder. "Come on. We need to find Nyssa now."
He led his companions out of the building. Both blinked at the sudden change in light, their eyes watering uncomfortably. The Doctor hustled them along the edge of the village, skirting the outer homes.
"Where are we going?" asked Tegan.
"To the one place that no one would think to look."