Leaning on the bat, Ace stood up shakily. She could hear distant cries, moans, shouting. She wasn’t alone here. There would be hordes of others, taken and trapped just like her, and Ace knew that she had to find them. She had to find the reason why she was here. In her dreams she’d been shown a premonition, but now she was a prisoner of her subconscious no longer. I can act, Ace told herself. Change things.

She brushed off her black bomber jacket, looked down at her badges, took strength from them. To how many alien worlds had she dragged her Blue Peter badges! Sometimes she’d imagined herself filming a Special Report from one of those far-off planets, relating the problems facing the inhabitants – or the casual visitor.

‘This one’s simple,’ Ace murmured. ‘Come here, and you’re royally stuffed.’

She hummed the Blue Peter theme tune to herself as she forced herself to walk like she meant it toward the sinister edifice on the horizon, striding up the sandy rise with all its sharp edges, gripping the bat like she was ready to strike something hard.

Night was falling fast, the sickly glow of the three sinking stars fading to reveal an alien night of dust clouds and nebulae. As she reached the top of the sharp, sandy slope, Ace saw scores more people moving towards the weathered fort, moving alone or in straggling groups. Young people, young … things, humanoid but with very different features, limbs or hues to their skin.

Her bruised spine tingled. The scene was straight from her dream.

She sensed they were walking to the building, like her, because there was nowhere else to go. She remembered her sensory hallucinations before, hearing her mother’s voice, smelling her old bedroom … the time-dilation effect had maybe pulled past events into her present. Perhaps her recurring nightmares had been the echo of future events – or rather, of events right now – thrown back through her consciousness in the same basic way.

I’m a long way out, Ace reckoned. Further than I’ve ever come before.

But where had her fellow travellers come from? Ace squinted through the gathering dusk, hoping to find potential allies, some race she recognised from her TARDIS travels.

Amid the legions trudging across the sands she saw two people who made her jaw drop in astonishment.

‘Chantelle?’ Ace shouted, stumbling forward. ‘Kim! What the hell …?’

For a moment she doubted her senses. But no: she didn’t know how, but it was them. She was sure of it.

Ace quickened her step, wincing as the sharp rocks bit at her feet even through the soles of her boots. Then she heard a sound like twigs snapping close by and a waft of musk and decay.

A single word sliced through her brain: Ratts.