Tessa felt herself being pulled across endless changes in floor surface; wind periodically blew across her face. She was no idea where she was and her companion’s endless droning voice made her nervous; he had outlined their life together for the next ten years, only stopping when he thought someone was in earshot. She was getting scared of him and waited patiently for her chance to strike.

It came sooner than she’d expected. They rounded a corner and found themselves at the edge of some scaffolding left from previous repairs to the building. Tessa felt the wind on her face; although she was almost blind she could just make out the grey blobs that were the steel walkways. As the Doctor turned to help her across she struck, hammering the knife into his arms. He screamed in pain and dropped, cursing at her. Grabbing a handrail Tessa began to make her way out onto the scaffolding; she couldn’t see far enough to tell if it was a sensible direction, but at least it was one.

Holmes, Lestrade and Watson flew through the building following the fading blood trail. Although much of the blood had rubbed off on carpets and tiles along the way there was still just enough to track and Holmes was on the scent like a bloodhound to its quarry. They all froze for a second as the scream echoed back from up ahead, Holmes drew his cane and Lestrade her ioniser.

'This way -- hurry.'

Rounding the last bend they stopped dead. A white-haired man dressed in a stained labcoat was collapsed on the floor, a knife handle sticking out from his arm. But out on the rusty and failing scaffolding was Tessa, now dressed in loose blue overalls, groping around in the air near the edge of the structure. Beneath, Holmes could see the boards were rotten.

'Miss Moriarty.'

She straightened and managed to feel her way enough to turn. 'Holmes!'

Holmes retracted his cane and made his way over to the edge. 'Listen to me, I want you to walk towards my voice, quickly and carefully.'

'But....'

'Don’t argue, just do.'

Behind them a shot fizzed overhead. Lestrade returned fire.

'Holmes, we’ve got company.' Tessa began to make her way across the wobbly boards back towards Holmes.

Suddenly the boards on the scaffolding cracked; for one awful second Tessa's face froze and then disappeared as the boards gave way beneath her.

She fell in darkness, bits of timber and metal impossible to avoid in the grey mess of her vision. She closed her eyes and flailed her hands. There had to be something to grab on to. Then she heard it -- the familiar hum of a hoverboard.

'Tess.' She recognised the voice immediately. It was Ling; the Dragon had come. Seconds later an arm wrapped around her waist and she felt the board under her feet. Burying herself in his shoulder to avoid the shrapnel as the scaffolding collapsed around them, she let Ling carry her away.

Holmes saw the entire thing from above as he stared horrified over the edge of the building. Grabbing Lestrade’s shoulder he pulled them towards a second door. 'Time to go, and now might be a good time to call for reinforcements.'

They fled through the door, Watson barring it with a piece of metal pipe nearby. By the time they got outside the building was shaking, the scaffolding which had been supporting the side wall gone; collapse was imminent. People fled the scene in all directions, many giving themselves up as the police rounded the corner a few minutes later to give chase. There was no sign of Moriarty.