She waits a few seconds and when there’s no response, tries again. The cold damp inside the narrowboat hits her. The Kingfisher is always chilly on the canal, even in summer, but March cold is particularly penetrating. On another night she might throw on her poncho but there are more pressing things. A moment or two later she tries Nevis for a third time and gets no response. She takes a breath, checks the sender and re-reads the text in case she has got it wrong.

Need speak now.

Honor thinks about calling the police but what will she say? A nervous tic starts up behind her eyes, like the ignition on the gas burner. Again she calls and again, nothing.

She’s up now and in the saloon, plucking her puffa jacket from the hook beside the steps to the deck. There’s a sudden tiny shock of fur as Caterine the Great, disturbed from her usual routine, weaves herself around Honor’s legs. Any other time the cat would be a comfort but tonight she steps round the animal and clambers up the steps onto a deck already slippery with rime. Frosty cobwebs sit on the glass windows, reminding Honor, unexpectedly, of a day, a few years ago, passing a happy hour or two on a school science project with Nevis to make ice from supercooled water, the seed a grain of rice thrown into the water bottle, the instant transition of water to ice, the cracking as it shattered. There is a bright moon and over the marshes a pink London sky. From somewhere far away comes the tinkly laughter of people partying on the water. A distant siren blares.