‘No!’ cried Mae. ‘It’s happening again!’ She tried to pull her wrist away from the Doctor’s grasp, to hide the face from view – but he held her arm firm.

‘I’m going to hurt you, girl!’ growled the face of Grandma Betty as it bulged out of the skin on Mae’s arm. ‘I’m going to hurt you bad! I’m going to make you pay for every moment you spent coveting my savings!’

‘But I didn’t want any of it,’ blubbed Mae. ‘I just wanted you to be well again.’

The face twisted and contorted as it grew in size, looking for all the world as though the old woman was trapped beneath the skin of Mae’s forearm, trying to force her way out.

Clara looked up and met the Doctor’s gaze. ‘Doctor?’

‘A sentient burn!’ proclaimed the Doctor. ‘An injury that can talk! A wound with a view!’ His eyes lit up at the final analogy. ‘It’s a new one on me.’

‘So what do we do?’

‘What we always do,’ said the Doctor matter-of-factly. ‘We give it a chance.’ He twisted Mae’s arm round so that the now almost fully formed head was facing him.

‘My name is the Doctor,’ he said. ‘Who or what are you?’

The face turned its scarlet eyes towards the Doctor. ‘I am the girl’s grandmother, of course.’

‘No,’ said the Doctor with a shake of his head. ‘Whatever you are, you are most definitely not Grandma Betty – unless, of course, Grandma Betty was born on a distant world and travelled thousands of light years to come here and start a family …’

He lowered Mae’s arm as a sudden thought occurred. ‘She wasn’t, was she?’

Mae blinked through her tears. ‘What? No!’

‘And she wasn’t made of plastic? Had a hand that flipped open with a gun inside?’

Mae stared at the strange man as if he was insane. ‘What are you talking about?’

‘I guess not, then!’ The Doctor raised the face to his again. ‘So I’d like you to tell me the truth. Who are you, and what do you want?’

The face hissed angrily and began to sink back into the skin of Mae’s arm.

‘Oh, no you don’t!’ cried the Doctor, blasting Betty with his medical tool and dragging the face back out into the open. ‘It’s very rude to walk off in the middle of a conversation! Now, tell me who you are.’

When the face spoke again, its voice had changed. It was deeper, more resonant – and it seemed to come from all around the room at the same time. ‘The Shroud shall feast!’

‘The Shroud …’ said the Doctor. ‘Never heard of you. How many of you are there? And what’s this feast?’

Before the Shroud could reply, the door to the office opened and a middle-aged woman with short, sensible hair entered. She was wearing a white coat and also had a stethoscope draped around her neck.

‘What are you doing in my office?’ she demanded.

The Doctor flicked off the green light. ‘It’s OK,’ he said confidently. ‘I’m the Doctor.’

‘No,’ retorted the woman. ‘I’m the doctor.’

Clara jumped to her feet with a smile. ‘And I’m a nurse,’ she said, holding out her hand, ‘but I’m undercover at the moment, in plain clothes.’

The woman looked down at Mae, who shrugged. ‘I don’t know who either of them are, or what they’re talking about. I just came here to get my burn treated.’

‘And now look what’s happened to it!’ cried the Doctor. Mae looked back at her arm to discover that the Shroud had now disappeared. All that remained was the original face-shaped burn mark.

‘I will ask you again,’ the woman said firmly, ‘and, this time, I expect the truth. What are you people doing in my office?’

The Doctor’s eyes grew wide. ‘Your office? Oh! In that case, you must be …’ he steered the chair back to the desk and began to rifle through the piles of paperwork. ‘Dr Mairi Ellison. Ooh, that’s a good name! Mairi!’ He rolled it around his mouth few times, trying different inflections. ‘MAIri! MaiRI! MAIRI! A name so Scottish, you can almost chew on it!’ He leapt up and kissed the air on either side of the confused doctor’s face. ‘I’m absolutely delighted to meet you, Mairi! You’ve got a lovely office here, but your desk could do with a tidy up.’

‘Oh, well … OK,’ said Dr Ellison. ‘Did I hear you say that you were a doctor as well?’

‘You most certainly did,’ beamed the Doctor, wiggling the end of his stethoscope in the air. ‘I’m a doctor as well.’

‘That still doesn’t explain what you’re doing in my office.’

‘Ah! Well …’ The Doctor looked to Clara for an explanation, but she just shrugged. ‘I, er … That’s it! Yes! I wanted a second opinion.’

‘On what?’

The Doctor grabbed Mae’s wrist again and held the burn out towards Dr Ellison. ‘What do you make of this?’

Dr Ellison pulled a pair of spectacles from her coat pocket and slipped them on. ‘It’s a scald,’ she said, examining the mark. ‘Pretty nasty one, too.’ She looked up at Mae. ‘What was it? Coffee?’

Mae nodded.

Dr Ellison removed her glasses. ‘Yes, I thought so. I did much the same thing to my own arm last year.’

‘Did you?’ asked the Doctor, twirling his strange medical tool in his free hand. ‘But the question is, could yours do this?’

He let loose another burst of green light and began to drag the face of Grandma Betty out from Mae’s arm once more. It began to roar angrily.

Dr Ellison backed away in terror. ‘What is that?’

‘This?’ asked the Doctor, holding up his bizarre implement. ‘It’s called a sonic screwdriver. It uses sound waves to vibrate a rare crystal found only in—’

‘Not that,’ interrupted Dr Ellison, pointing at Grandma Betty. ‘That!’

‘Oh, they’re called the Shroud,’ said the Doctor, ‘but aside from that I’ve no idea. I do know, however, that it must be hidden from sight at once. Do you think you could dress Mae’s wound for me? I’ll do my best to keep Betty under control while you work.’

Flicking from one setting on his sonic screwdriver to another, the Doctor fired burst after burst at the bulging face until one of them had the desired effect of forcing the Shroud to retreat back into Mae’s forearm.

‘Now!’ cried the Doctor, holding the sonic steady.

Dr Ellison grabbed a first-aid kit from her desk and, with trembling fingers, she laid a sheet of gauze over the burn mark, then began to wrap a bandage around Mae’s arm to keep it in place.

‘Will that work?’ Clara asked the Doctor. ‘If the face is hidden from view, will it leave Mae alone?’

‘Haven’t got a clue,’ the Doctor replied. ‘But at the moment, it’s the best I can think of. The Shroud must be the reason the TARDIS brought us here in the first place, but—’

His words were drowned out by a piercing scream from the corridor outside. He flashed a grin at Clara. ‘They’re playing our song, dear.’

Clara held out her hand. ‘Care to do the corridor quickstep?’

The pair dashed out of the office, closely followed by Dr Ellison and Mae, the wound on her arm now properly dressed.

‘This way!’ cried the Doctor, racing off in the direction of the scream. But he had only taken a few steps when a second scream rang out – coming from the opposite direction.

The Doctor stopped, turned towards the second scream, and then spun back to face the first. Both were growing in volume and each sounded as urgent as the other. He hopped from foot to foot, jiggling the sonic screwdriver anxiously. ‘Argh!’

‘It’s at times like this we could do with two Doctors!’ exclaimed Clara.

‘But we do have two doctors,’ said Mae.

The Doctor twisted on the spot and grabbed Mae by the shoulders. ‘Yes!’ he exclaimed. ‘Of course! Brilliant! We can split into teams! Mae and I will be Team A … Dr Ellison – Mairi – you and Clara can be Team C.’

‘What happened to Team B?’ asked Clara. ‘Never have a Team B,’ said the Doctor earnestly.

‘It’s like Plan B – always second best. Whereas Plan C and, by extension, Team C, is usually the result of fresh thinking.’

‘Team C could stand for Team Clara,’ Clara suggested.