The Master growled and bashed the wall of the console room in frustration. It had been three weeks since they'd received the message, and they were no closer to finding Thief. The TARDIS hummed in disapproval and the Master muttered an apology. He hadn't meant to annoy her, but it was so frustrating! The drums in his head were louder than ever. He was interrupted by a cough from the doorway. It was Clara.

"I brought you some tea."

"Thanks," The Master took the mug from her hands and stared into the depths. Clara looked across the room at the Doctor who shrugged.

"Do something," Clara mouthed at him.

"What?" he mouthed back. She shrugged. The Doctor settled for resting a hand on the Master's shoulder while Clara went to look at the scanner. "We'll get her back, Koschei," he said softly in Gallifreyan. The Master said nothing, but he didn't shrug the Doctor's hand off his shoulder either.

"Uh, guys," Clara said. "I think you should see this." They both ran over. On the scanner were several Gallifreyan characters. "What is it?" Clara asked.

"Space-time coordinates," the Master cried. "From Thief as well! It'll lead us straight to her." He spun and grabbed Clara by the shoulders, planting a kiss on her forehead. "You brilliant girl, Clara Oswald, we'll find her yet!"

Ten minutes later, when the TARDIS shook and knocked him over for the fifth time he was regretting his decision to let the Doctor drive. "Do you have to hit every bump?" he demanded, catching Clara by the shoulders when she stumbled into him.

"This isn't easy, you know," the Doctor shouted, pushing buttons and pulling levers frantically.

"We let me do it then!"

"You? Fly my TARDIS? Not after last time."

"At least I passed my flying exam. The instructor said it would be a sorry day for the universe if you ever got your hands on a de-materialisation circuit." He paused as they were flung across the room, Clara landing on top of him. The TARDIS had landed. "I'm starting to think the old instructor was right," the Master grumbled, giving Clara a hand to help her up.

"Great," The Master grumbled. "We're stuck on a ship in the middle of nowhere and we can't even find the control room."

"We don't want to find the control room," the Doctor reminded him. "We just want to find Thief and get out of here."

"And how are we supposed to do that when we don't know where we are?"

"You were the one who wanted to come here."

"Well maybe if your sonic screwdriver was working we'd have found her by now."

"I told you, it doesn't do wood!"

"Children, children, squabble later," Clara said, trying not to laugh. "Why don't you try reading the signs?" They both looked at her.

"Signs?" the Master queried. Clara pointed to the ceiling. Right at the top of the wall were some Gallifreyan characters.

"Honestly," she said. "You could try looking."

They had followed the signs to the brig in the end, not the control room, although the Master had been torn between finding Thief and giving the Rani hell. "Can you hurry up?" he demanded. The Doctor was trying to open all of the cell doors, but so far all the ones they'd checked were empty.

"Shush," the Doctor said.

"What?"

"No, seriously, shush. I can hear something." They all listened. Floating down the corridor was the sound of someone singing.

"That's Thief," The Master said. "That was always her favourite song." They ran, following the sound down the corridor. The Master felt hope rising in his hearts. They were so close! He would finally be able to see his daughter again.

They reached the cell door and the Doctor set about trying to open it. The Master paced impatiently.

"Hurry up!"

"I'm trying. The Rani doesn't make her prisons easy to break into you know." Finally, after an agony of waiting, the lock clicked. The Master flung open the door, and felt his hearts stop.

It was empty.

On the wall, in Gallifreyan, ten words were written.

You didn't think it would be that easy, did you?

In the Master's head, the drums roared.

Clara couldn't read the words on the wall, but from the look on the Master's face, she could guess what they meant. "Clara," the Doctor said quietly. "Get out of the way."

"What?"

"The rage of a Time Lord is a terrible thing, Clara. Get out of the way." He pulled her backwards as the Master turned. There was nothing even remotely human in his eyes in that moment. He walked out the door, energy crackling around his hands.

"We have to go after him!" Clara cried.

"Yeah, just don't get in his way."

The Master didn't even seem to have to look at the signs, he just went the right way. The Doctor and Clara hurried after him. "Ah," the Doctor said. "I wondered where that corridor lead. Control room, here we come!"

"Doctor." Clara said disapprovingly.

"What?"

"Do you have to make a joke out of everything? In fact, don't answer that. I'm not sure I want the answer."

Sure enough, the Master lead them straight to the control room, where the Rani stood at the controls, looking down at the burning world beneath her. On the far side of the room, a young girl was being held by two guards, but the Master didn't see her. A burst of energy hit the Rani in the ribs and knocked her backwards. "Where is she?" The Master demanded.

"What?" The Rani looked to the girl in the corner, confused.

"I said, where is she?" The Master raised his hands, ready to blast the Rani again, but then someone grabbed his arm. In the background he could hear shouting, all variants on, "Will someone stop that lunatic?" but he ignored them, looking down at the person who had grabbed his arm.

It was a young woman, about sixteen, with short ragged black hair and curious green eyes. She looked up at him, desperately. "Father stop! It's all right, I'm here." In a dream, the Master reached up to touch her face. She was here. She was alive. He hugged her tight, and there was a deafening silence in his head where the drums used to be. And then he heard it.

thump-thump-thump-thump thump-thump-thump-thump

That was what he'd been hearing. That was what the drums were.

The heart beat of a Time Lord.