She isn’t shocked, exactly, by Kirsten’s disappearance. There is a part of Emily that has always been waiting for Kirsten to leave – to emigrate or become famous or die splashily, like from an overdose or in a plane crash. Kirsten is the wicked, mischievous twin. The one who wanted them to wear matching outfits, play pranks on their teachers, kiss each other’s boyfriends.

‘It’s like a bad marriage,’ Emily explains to the group. They nod compassionately. ‘You don’t get on, but you’re paired up. There’s no getting away from each other.’

This is Emily’s first time at the group. She clings on to her cookie for dear life. They are all here because they have lost a twin. They are all here to share. The group leader goes first, telling his story with the gravity and pathos of someone used to unfurling his pain. Everyone’s story is clear-cut in its tragedy. Their twins are lost to cancer, suicide, road traffic accidents. Emily’s is the only one unaccounted for.

‘At first I wasn’t worried,’ Emily tells them. ‘Because, well, she’s wild. An artsy type, you know? She has a habit of taking off whenever it suits her.’

‘You’re still talking about her in the present tense,’ observes the group leader. He’s an attractive man her father’s age, whose smile doesn’t trouble his eyes.

‘Well, yeah. She’s not dead.’

There is an awkward silence.

‘I’ve brought posters . . . missing person posters. They’re in a stack on the refreshments table if anyone would like to take one. I’d really appreciate it.’

The group leader leans forward, elbows on his knees, coffee cup clasped: benevolence itself. ‘Emily, was it? Emily, this is a support group for people whose twins have passed. I am sure there are plenty of groups for the loved ones of missing people.’

Emily’s legs tense; she is ready to bolt. ‘Sorry. I just saw a flyer for people who’ve lost a twin. Which I have.’

‘She’s right,’ says a woman with dreadlocks. Her story is the twin she lost to leukaemia when they were eight. Her story is survivor’s guilt. ‘Who are we to question her pain?’

Read the rest of the story on Granta.com here.