There was another silence and then Mama spoke, so quietly that I almost missed it. But I didn’t miss. And it landed like a blow to my heart.

‘Sometimes,’ she said, ‘sacrifices must be made … ’

‘Sacrifices?’ There was a snarl of contempt in the Doctor’s voice.

‘It was necessary!’ hissed Mama. ‘I had to know how much of the venom would produce an antitoxin. To immunise myself! Don’t you see? It was necessary—’

But she stopped dead in her tracks. Because I had left my hiding place and, in a flurry of skirts and clacking cane, was standing in the doorway.

I tried to be calm, to keep my voice steady, to not betray myself or my shattered nerves but all that came out was a pathetic and bleating: ‘Mama?’

I wish I could have read the expression on her face but, as ever, all was dark to me.

Except now there was a ray of light. The light of truth which my Monster had provided! But – oh – what a terrible truth it was.

‘Is it … is it true?’ I ventured.

‘Ada … ’ Mama’s voice trailed away.

And in that moment I knew all. ‘It is. It’s true.’ A big, fat tear began to roll, unbidden, down my burning cheek. ‘True. TRUE!’

I heard Mama’s footfall approaching me. ‘Listen to me, child.’

I began to shake my head silently, crushed beyond expression. Then I heard the Doctor’s gentle voice. ‘Ada—’

But gentleness was the last thing on my mind. I sniffed back those salt tears and lashed out with my cane, swishing it back and forth like the Reaper’s scythe!

‘HAG! You perfidious hag!’ I screamed at Mama. ‘You Virago! You Harpy! All these years I have helped you. Served you. Believed in you. Did it count for nothing? Nothing at all?’

I felt my cane connect with something and Mama let out a cry. It felt wonderful, wonderful I tell you, to finally give as good as she gave! I swung the cane again but then felt it grabbed by her strong hands and we wrestled for control. As we did so, I heard a flurry of activity close by and the Doctor’s voice.

‘Hang on, Clara, I’ve got the sonic screwdriver!’

‘Yeah?’ said the friend. ‘Well I’ve got a chair!’

Suddenly, there came a tremendous crash and a shrieking, protesting scream from Mama’s calculating engine. There was wave of heat and I heard the familiar crackle and sizzle of flame. Clara’s chair had evidently done its work.

Mama let out a great cry of anguish. ‘Noooooo!’

‘Yeah,’ said the Doctor. ‘Chairs work. I’m very pro-chairs.’ He sniffed. ‘Oh dear. I’m afraid your rocket isn’t going anywhere, Mrs G.’