At school, during one of her regular week-long periods of being un-friended by her friends, Zoe walked into the toilets in the library, to find two older girls sitting on the floor under the hand towels, stamping a pile of leaflets with green stars and stickers. She knew exactly who they were: Stella Armitage and Tara Gill. They looked up at her and grinned.

‘Here, take this,’ said Tara, handing her a leaflet. With her shaved head she could’ve been a boy. It was rumoured she had a triangular tattoo on her ankle. ‘We’re having a gathering this afternoon.’

‘You’ll come, yes?’ said Stella, who wore green nail polish, had a nose ring and played the fiddle.

Zoe took the leaflet and retreated to a cubicle. As she peed, she read, The polar ice sheets are melting. The time for inaction is over. See you@5, Library Meeting Room.

When she came out again, the girls had gone, but she could smell something of them in the air still, through the air freshener, a smoky woodiness. The Green Club. That would be something to tell her father, the man on the telly, the next time he ever stopped to ask her anything about herself. That she, like him, was an environmentalist.

It turned out that the Green Club met to consider, not the environment as such, but environmental actions. Zoe had never heard of an action before the afternoon she watched the video that Mx Thompson played, with its high-octane television footage of scruffy people shouting at policemen. Afterwards, Mx Thompson (they/them/theirs), skinny as a razor clam, pale, silent, with freckles the colour of their gold-red hair, one of those teachers who liked the sound of their own voice much less than normal, explained that it was a road protest; that the protesters were protecting trees; got them to think about the sacred oak in Celtic culture; how the human love and veneration of trees was deep in our psyche; which is why we all put up fir trees in our homes at Christmas; which was why these young people had camped out to protect ancient woodlands from being decimated by careless governments.