We search the whole of Bao Mansion for Por Por. I don’t want to believe that she is dead. I look upstairs. Ting Ting searches downstairs, then together we go through the servants’ quarters and the inner garden. We call out her name. We look in every place we can think of, but we can’t find her anywhere.

‘Just using our eyes is not good enough,’ I say to Ting Ting as we stand in the reception room.

‘What do you mean?’ she asks.

‘Well, lately I feel as though I’m connected to Por Por somehow. Like there’s a thread that joins us together. And no matter how far away I am from her, I know where she is … or I should know. So I’ve been thinking, if we both stand very still, maybe one of us can feel this connection more strongly and it will lead us to her.’

Ting Ting looks at me with grudging respect. ‘It’s worth a try. But wait. Shouldn’t we destroy the talismans in the strongbox first?’

I had forgotten all about the strongbox. Ting Ting was right. Even though the ghost of Shen Da Pai no longer existed, those evil things still held power over Bao Mansion.

We go back to the hidden room. This time Ting Ting goes down while I stand guard. I see her strike the match and drop it into the box. The light is so bright that for a moment I have to look away. A horrible acrid smell like a rubbish tip on fire fills the room and I hear Ting Ting coughing. Then it’s dark once more.

‘Those things were so disgusting!’ Ting Ting says, climbing out of the hole. She wipes her nose and mouth with her sleeve then spits on the ground.

‘While you were down there I got this strong feeling that Por Por is upstairs somewhere,’ I say. ‘And I know in my heart that she is still alive.’

‘I hope you’re right,’ Ting Ting replies.

We search every room upstairs but they are all empty. Finally, we come to Por Por’s old room.

‘Hey, what’s that?’ Ting Ting points to a big crack under the window with something jammed inside it. She crosses the floor and pulls out a flat parcel wrapped in newspaper. She unwraps it carefully.

We both gasp when we see that it’s Por Por’s very own mingshen mirror. But where is Por Por?

‘Wait,’ I say, filled with dread. ‘There’s something inside it.’ A flicker passes underneath the glass. The figure is grey and shadowy at first. But then the image grows closer and clearer. My heart sinks when I see Por Por standing in a bleak empty space, staring out at us, looking lost.

‘Por Por!’ I say, running my hand over the glass as if I can reach out and touch her.

‘Are you all right, Por? Are you hurt?’ Ting Ting says.

Por Por looks blankly around at her surroundings. She doesn’t know we are here. She can’t see or hear us.

‘How are we going to get her out of there?’ I say in desperation.

‘We can’t,’ says Ting Ting. ‘Once a ghost-hunter is trapped in her own mirror, she is trapped there forever.’

‘But there must be a way to unlock it,’ I say, even though I remember Por Por herself telling me the same thing.

Ting Ting leans against the wall and a single tear rolls down her cheek and drops onto the mirror.

The surface quivers like clear jelly. It’s so slight, I almost miss it. I peer closer.

‘Ting Ting, wait!’ I say. ‘Look at the mirror. Your tear, it did something to the glass!’

‘What?’ She looks down. Another tear falls onto the surface and this time we both see it quiver. ‘It’s true!’ Her face breaks into a huge smile. ‘Quick, sit down with me. We have to cry as many tears as we can.’

‘I think I know an easier way,’ I say.

I lead her down the stairs and out to the inner garden. I kneel down beside the lake. ‘Your tears dissolved the surface of the mirror because they’re pure,’ I explain. ‘I remember Por Por telling me that no water is purer than the water in this lake. So it should work in just the same way.’

I hold the mingshen mirror just below the surface. At first nothing happens. But then, just as before, the surface grows wobbly like clear jelly and slowly begins to melt away. I see Por Por clearly now, lost inside a deep cavern. She still can’t see or hear us. And unless she climbs out herself, I’m not sure how we’re going to free her. We can’t just plop her out into the water like we do the ghost fish. And I’m definitely not going to put my hand inside the mirror. I look at Ting Ting.

She raises her eyebrows then shrugs. ‘It’s worth a try.’ She takes the mingshen mirror from me and turns it upside down over dry land. Then she taps it on the back once, sharply.

As if by magic, Por Por plops out, rolls along the ground in a tight ball and stops when she gently hits a large boulder.

She sits up and looks around, dazed. Then she says accusingly, ‘What are you doing?’

We hug Por Por like she’s a baby, laughing and crying and all trying to speak at once.