But the hymns wear out. After three days she is running through one after another, abandoning this one mid-chorus, that one mid-verse, a dozen after only a lungful of bars: a desperate chorister flicking through her mental hymnbook to land on something, something… but the faces are breaking through, and the smell of chlorine, and a tightness around her wrists, and something jagged as broken glass stuck in her throat. And she is lost, drowning, until she finds, at last, a tune that quells the panic. At first she can’t identify it, but as the fear subsides she can think again. It’s a nursery rhyme.

‘Three Blind Mice’ at a gallop lasts until she tips into sleep. In the morning, it’s ‘Oranges and Lemons’ until the sunlight slopes off the end of her bed. And then one that sticks. One that counts, and needs its words.

One, two, three four five, once I caught a fish alive.

Any incursion of memory, she only has to sing a little louder and she’s back into numbers.

Six, seven, eight nine ten, then I let it go again.

A flash, a breath.

Why did you let it go? Because it bit my finger so. Which finger did it bite? This little finger on the right. One, two, three four five…

And all day, and all night, and all week it contains her. As long as she sings, she is safe. She eats around it, humming only for as long as it takes to swallow. She stares into the eyes of the staff, singing, singing. She knows they will take it as madness, though it is the opposite. It is what keeps madness at bay.

One morning a woman comes. A woman with forms, a hot chocolate voice, elf-shoes, and a case like a drill might live in.

It’s the friend of Dr Logan’s. One, two, three four five, once I caught…

With two guards, they travel to a private clinic with an MRI machine. The MRI machine is Just to check we’re in the right area, says the woman. Are they in the right area? It’s very white, very clean, very hold-still-while-I-remove-this-vital-organ.

Then I let it go again.

The woman opens the case and brings out something that looks like a hairnet, trailing wires.

Which finger did it bite?

The woman’s words slip through the gaps between lines.

Non-invasive, she says. Like a hat.

She positions the hairnet on April, plugs the trailing wires into something in her drill case, then repositions the hairnet, twice.

One, two, three four five…

The MRI machine looks like it could kill you. Cook you from the inside out, like a microwave. April doesn’t mind. That’ll be fine. That’ll be perfect.

Six, seven, eight nine ten…