A few bursts of sonic energy later, the Doctor was able to lift the keyboard off the console. ‘Goodness!’ he exclaimed, looking at what was underneath as he started to screw the pipe in place on his gadget. ‘I wondered where that had got to.’

‘What is it?’ asked Clara, looking round the Doctor’s arm. On the console, underneath where the keyboard had been, was a small square box with two switches at the top. Above it, in what appeared to be felt-tip pen, was written ‘Fast Return’.

‘The Fast Return switch,’ said the Doctor, whirring screws into the pipework with his sonic. ‘Think of it like a rewind button for the TARDIS. One side deals with time and the other with space. Press them and we’ll end up at our previous location, as though we’d been pulled back there by a bungee cord.’

‘But why was it hidden by the keyboard?’

‘Must have been covered up during my last redesign. I haven’t used it for a long time now,’ said the Doctor. ‘Not since it got stuck and tried to drag me back through the beginning of the universe.’

‘I can see how that would be a problem.’

The final screw in place, the Doctor grabbed the pipe at the end of his gadget and checked that it was now secured. ‘Ready?’ he asked.

Clara grinned. ‘Ready!’

The parade was one of the strangest things that Warren had ever seen. Dozens of military jeeps and armoured vehicles lined the road outside the hospital, their deep green camouflage hastily covered with colourful curtains and bedspreads. Standing in the back of each truck was a Clown or two, ready to perform.

In front of the military machines, the Clown band were warming up their instruments. Flip Flop was with them, holding out a radio handset which fed directly into a huge pair of speakers strapped to the top of a tank. As the musicians played, their song was amplified out in every direction.

Before the musicians, several dozen children waited nervously, bundles of cotton pillowcases bundled under their arms. The Clowns had applied a little face paint to each of the kids, giving them red noses and drawn-on smiles. Despite their nerves, the youngsters giggled at the sight of one another. Mae and Orma stood with them, trying their best to keep spirits up among the group.

And there, at the head of the parade, were Wobblebottom and the Doctor. The Clown was spinning a drum major’s baton, while Clara helped the Doctor into a leather harness that allowed him to carry his gadget in front of himself, and angle it either left or right.

‘What’s it called?’ Wobblebottom asked, eyeing the invention with interest.

‘I’m not sure yet,’ said the Doctor.

‘So give it a name,’ said Clara.

‘Well, it amplifies emotions, so it could be the Emotion Amplifier … No, on second thoughts, forget that. It’s a rubbish name.’

‘What about the Fun Gun?’ said Clara as she fastened the buckle on the second strap.

‘No!’ cried the Doctor. ‘I’m not having anything with “gun” in the name!’

‘OK,’ said Clara. ‘The Happy Slapper!’

The Doctor stared at her. ‘Are you insane?’

‘You could call it the Fun Flinger,’ suggested Wobblebottom.

‘Yes, only it doesn’t so much fling the fun out of the big end as squirt it out,’ said the Doctor. He raised a finger to silence Clara. ‘Whatever you’re about to say, Miss Oswald, forget it!’

Clara shrugged. ‘Whatever you call it, we can still only use it on one group of people at a time, can’t we?’

The Doctor grinned, his eyes sparkling. ‘This is the best bit,’ he said. ‘This is the bit where you get to call me a genius! Because of the tragic events here yesterday, Dallas is filled with television crews from all over the world. I asked Captain Keating to send someone out to tell them all about this, and here they come now …’

Clara heard the sound of engines and looked up to see dozens of vans and trucks approaching, each one painted with the logo of their news team or TV station. Many of them had antennae bobbing about on top as they drove.

‘But haven’t they been affected by the Shroud?’ asked Clara.

The Doctor tried not to look smug, but didn’t exactly pull it off. ‘TV reporters,’ he said. ‘Camera and sound operators, technicians, producers – all of them hardened against the less savoury side of the news, just like Mae.’

‘So they can hold off the Shroud!’ cried Clara, clapping her hands. ‘OK, I’ll give it to you this once – you’re a genius.’

The Doctor raised a finger. ‘I’m not done yet …’ He smiled. ‘They’ll broadcast the concentrated joy produced by …’ he hoisted up his gadget, ‘… whatever this thing is called to every country on the planet, severing links with the Shroud worldwide.’

‘Even back at home?’ asked Clara.

‘Well, that looks like a BBC van to me,’ said the Doctor, standing on tiptoe to see over the gathering gaggle of reporters. He checked his watch. ‘So back in Britain, it’s just about teatime on Saturday 23 November 1963 – and the fun is about to start!’

The Doctor turned to survey the waiting procession. ‘All right, everyone!’ he called out. ‘Drivers, follow my lead. Kids, ready with the pillowcases. And Clowns, just like you did back on Semtis – once more with feeling!’ He turned back to Wobblebottom with a smile. ‘That’s it! I’ll call this thing the Once More With Feeling.’

‘Then let’s give it a go,’ smiled the Clown. He blew his whistle, and he and the Doctor set off at a march. Behind them, the musicians began to play, the children skipped along to the beat and the military vehicles set off at a crawl. On the back of each truck, the Clowns started to perform. They tumbled, danced and juggled, and twisted long balloons into the shapes of dogs, birds and more.

Warren watched from the steps of the hospital as the parade began. Despite the trouble the world was in, he couldn’t help but smile at the spectacle. It was one of the happiest groups of people he had ever seen gathered together in one place. Slowly, the procession snaked its way out of the car park and past the waiting Shroud victims on the sidewalk beyond.

As the Doctor approached the first group of people – each still holding hands with a woman in a blue dress, he spun the Once More With Feeling to face them and pressed a button on the side of the gizmo. There was a whoosh, and a jet of compressed happiness blasted out of the funnel, ruffling the victims’ hair. The porter from the hospital was there, and he chuckled.

‘Now!’ called the Doctor over his shoulder. Mae grabbed a pillowcase from one of the children – a boy named Arran – and dashed over to the porter. In one quick move, she pulled the pillowcase over the head of the Shroud holding his hand, obscuring her face from the man. He laughed again as another burst of happiness hit him and – with a piercing shriek – the Shroud beside him vanished in a shower of blue sparks. The porter stumbled backwards, where one of Captain Keating’s soldiers was waiting to catch him.

‘It works!’ cried Wobblebottom, tossing his baton in the air and waving to urge more fun out of the Clowns.

The Doctor grinned as the porter was helped back towards the hospital by the soldier. ‘The Shroud’s veils are semi-transparent,’ he explained. ‘Those affected can see their loved one’s eyes through the material – but not when we cover them with a pillowcase. It breaks the mental link – just like it did with Mae when we bandaged her wound. With any luck, unaffected people all over the world will be copying us.’

Slowly, one by one, the victims of the Shroud smiled, giggled and guffawed. With each laugh, Clara, Mae or Orma slid a pillowcase over a Shroud’s head, obscuring their features from view. Scream after scream rang out as the aliens exploded into shimmering sapphire particles.

Crowds gathered at the sides of the road, people calling out to the Doctor to aim the Once More With Feeling in their direction and free them from the creature holding their hands. Further back in the group, Mae couldn’t help but notice the similarities between this parade and the one she had witnessed the day before that had started all of this.