Bill and the Doctor sat side by side on the short brick wall of the barrier line, looking out at the two rising suns peeking up over the horizon of the ocean beyond. The water was a brilliant teal color, the sky a blend of orange and yellow hues. Bill's eyes watched the waves of the water and the curling clouds with wonder in her bright eyes

"It's-"

"I know."

"-really humid. Did we really have to walk that far?"

The Doctor scoffed, turning to her in disbelief. She smiled at his gaping mouth and nudged his shoulder. "I'm joking. It's beautiful!"

He bit his bottom lip and turned back to the magnificent sight in front of them, but Bill's curiosity had been awakened.

"Two suns, though. Doesn't that have any effect on the atmosphere? Like, is it hot because you made us hike up three mountains, or is the whole planet just a furnace?"

The Doctor replied defensively. "It wasn't three mountains."

Bill rolled her eyes at him, and he surrendered. "Okay, it was a pretty long walk. But two suns do usually create a much hotter atmosphere." A distant look came into his eye. "My planet had two suns. It was practically a desert where I grew up."

Bill's head perked up at the mention of the Doctor's planet. Insights into her tutor's personal life were few and far between. "What did it look like? Tatooine?"

The Doctor shrugged. "More or less."

Bill let some air out of her nose, causing the Doctor to furrow his eyebrows at her. "What?"

She shook her head. "No, it's just...you grew up with two suns over you all the time and you're still paler than milk. I hope you had aloe on your planet."

The Doctor made to reply, probably to comment that he looked a bit different back then, or explain his planet's atmospheric conditions in more detail, but a shudder suddenly pulsed through the wall they were sat on. His eyes widened. "Bill. We need to get away from the barrier."

She turned to him with unwitting horror on her face, but before she could reply or make a move, the wall shuddered again, more violently, and she and the Doctor were both thrown onto the sandy beach below. The ground seemed to be vibrating beneath her fingertips.

"What is that?"

The Doctor jumped to his shaky feet and reached out for her hand. "Something we need to get away from."

Bill grabbed his hand and stood beside him, looking out at the ocean as a giant wave rose up not twenty feet from the shoreline. "Ugh, is that a tsunami?"

The Doctor followed her gaze, his face falling. "No. It's something much worse than that. Back over the barrier. Go!"

Bill grabbed tighter onto the Doctor's hand as they dashed back to the wall, a shadow falling over them both. Soon, even the wall and beyond were cast into darkness. Bill put a hand up on the bricks to try and levy herself up, but a sudden, loud roar just behind her caught her curious attention for just a moment. She nearly screamed.

An enormous blue creature, still partially in the water, had made its way up the beach, now standing directly behind her and the Doctor. Its jaws were open wide as it howled in triumph, though its teeth were rounded and unthreatening. What terrified Bill were its outreaching arms, wide as a small apartment blocks and shaped like flippers, gliding across the beach, picking up every grain of sand in their path. Both of its arms were making way for her and the Doctor, as if to scoop them both into its hands.

The Doctor locked eyes with his young companion just seconds before the sand beneath his feet gave way above the giant webbed hand and he was thrown onto his back. Bill followed almost immediately, only allowing herself to scream when the creature started lifting them off of the ground. The Doctor squeezed her hand in what he hoped was a comforting manner as they rose higher and higher above the alien world.

Just after Bill shut her eyes to wade off the vertigo sweeping through her, the flipper suddenly jerked up into the air and she and the Doctor were thrown unceremoniously into the air, high above the water. Their hands were wrenched forcefully apart, and suddenly they were falling further and further from each other. The Doctor's hearts beat against his chest as he scanned the whirling sky in front of him for Bill.

"Bill! Bill!"

He heard his own name shouted back at him, but his senses were stunted as the ocean grew below him, murky and seemingly endless. He shut his eyes just in time for the water to rush over his body, mind sinking into unconsciousness from the impact.

Just a second later, and ten meters away, Bill landed in the water, rather hard. She dropped ceaselessly into the abyss of the alien ocean, eyes closed even deeper in unconsciousness than the Doctor.

The Doctor's eyes shot open a moment later, and he realized he was using his respiratory bypass system to breath, his lungs and throat filled partially with salty water. He shook his head to clear it and looked around him, remembering suddenly what had brought him here. One thought came to his mind: he had to find Bill.

He pulled his Sonic out of his inside pocket and turned on the light, eyes darting across his surroundings frantically. The more time he took to find Bill, the worse her condition may be.

His legs kicked the water, free hand pushing steadily as he gazed around the dark, endless chasm. At least, he thought, the creature was nowhere to be found.

As his eyes landed on a form that looked eerily human, however, his gratitude dissipated into an endless stream of prayers and pleads. He forced himself forward, dread forming in his oxygen-deprived lungs and hearts. His entire body ached, but he surged on until Bill's arm was finally firmly in his grasp, too limp. The Doctor looked her over and found her leg caught in knotted seaweed.

With a grunt, the Doctor turned the Sonic to face her shoe and changed the setting, keeping a tight hold his on his companion's arm. A second later, nothing had changed. Five more seconds later, still nothing had changed. The Doctor hit the device against his head in frustration. Of course! Sound waves travel differently through water than through air. Stupid, stupid Doctor!

Instantly, he began manually untying the kelp and slippery green seaweed, tearing it apart in his anxiety and growing fear. As soon as Bill's leg was freed, he stuffed his Sonic back in his jacket, grabbed Bill under the arms, and kicked upwards. His chest felt like an elephant were sat on it, and his head was swimming. The growing light streaming in from the sun was the only indicator that he was going the right way.

Finally, his face broke the surface, and the Doctor began coughing and sputtering up water, hearts pounding as he realized Bill was not doing the same. His head turned this way and that, searching for land, which he found with a thankful sigh and a tightening of his hold around his friend's body. "Stay with me, Bill."

The journey back to shore felt endless, as seconds passed like small eternities. The Doctor grew ever more frantic as his legs worked double time to get he and Bill to land, his arms struggling to keep her face above the surface of the taunting water. If he never went swimming again, it would be too soon.

When his feet touched the bottom floor of the ocean, not five feet deep, the Doctor nearly cried out in delight. But one look at his companion, drenched and unmoving in his arms, silenced him. He carried her quickly out of the water and onto the stable, wet mud of the shore, dropping to his knees beside her. His fingers were shaking as he touched her throat, and his hearts nearly stopped as he failed to feel a pulse.

"Bill, don't. Don't."

He didn't even know what he was saying as he laced his fingers together over her chest and began compressions, mind too addled to bother counting or keeping in proper time. When he felt his arms going sore from the repeated motion, he moved closer to her face and pinched her nose. "Bill, please."

He a big lungful of air into her mouth, then noted her moving chest to be sure he was doing it correctly. Once more, he repeated the action, then shifted back to her side. His knees were properly aching now, along with every other part of his body.

Again, he pumped her heart with both of his hands, putting all of his body weight into his palms. With gritted, chattering teeth, he chided, "I should've known...shouldn't have come here...never ends well."

When Bill failed to respond to the compressions, the Doctor moved back to her head, his eyes stinging. Silently, he pinched her nose and held her head back with gentle fingers on her chin. He breathed in deeply and, praying and pleading with the gods, exhaled into her mouth.

Suddenly, she shuddered, coughing up the disgusting, salty water. The Doctor sank down in relief, rubbing circles on her back to calm both her and himself.

"Breathe. Breathe, Bill. You're alright. You're alright, just breathe."

Bill turned up to him. She was still weak, but her lips twitched into a smile. "Doctor...saved me."

The Doctor pulled her against himself; rubbing her arms to warm her. "Shhh; I got you. I got you."

Bill furrowed her eyebrow at him as she eyed his quivering lips. He was shaking more than she was, and his eyes looked almost bloodshot with unshed tears. She shook her head and tried to make a joke. "You actually had to be a proper doctor for once. Not just a professor."

It was when the Doctor failed to chuckle that Bill became worried. "We better get back to the university. Nardole will have your head if he knows you've been away again."

Finally, the Doctor broke out of his trance and helped Bill get to her feet. His silence, however, remained unbroken even after Bill had left his university office to change from her wet clothes. Now he simply sat at his desk, staring at the wall. Water dripped from his coat and stuck his hair in odd directions where it had partially dried.

Nardole entered just after Bill left, irate as he took in his boss' dishevelled form. "Sir, you can not keep running off on adventures, hoping I'll watch the vault. What if something happened? What if one of you got hurt?"

The Doctor closed his eyes, but instantly the image of a never ending abyss of water filled his head and his eyes opened wide. "Nardole, please."

"No, I'm not going to stand around here taking over your job every time you get bored. I did not sign up for that."

The Doctor put his face in his hands, and Nardole suddenly realized something was wrong. His demeanor quieted, shoulders slacking from their previous high-strung tension. "Sir?"

The Doctor dropped one hand to the desk and scratched the back of his head. "We...we nearly drowned. Bill...Bill almost drowned. I had to resuscitate her. I thought...I thought."

The Doctor was stammering. The Doctor never stammered. He never hesitated. And he definitely never had tears in his eyes while he talked about an adventure; even one that went wrong. Nardole rolled a chair over and sat beside his friend.

"Are you alright?"

The Doctor's eyes were distant. "She wasn't breathing. And my chest was all watery. My arms hurt but she wasn't breathing."

Nardole and Bill had joked about the Doctor being reluctant to bare his emotions; they had even made a game of it whenever the Doctor got teary at a commercial or laughed heartily at a comic book. But this was so, so different. Nardole put a hand on the Doctor's shoulder.

"Doctor, look. You saved her. Bill is fine. You're fine. Everything is okay."

The Doctor breathed in shakily. "I'll...I'll stay on Earth. I won't go anywhere. I'll just lecture for a while." He met Nardole's eyes. "I promise."

Nardole gave him an encouraging smile and patted his shoulder. "I'll make some tea while you get changed. You're getting your office all wet. If I were human, I'd be fuming about the antique wooden floors you're ruining."

The Doctor smiled, a good natural smile, and peeled his soaking jacket off while Nardole went off to the TARDIS kitchen.