"He wants you to look after it because he trusts you." Gulp. This is such a sweet letter from Joe's mother, and he's one of the gentlest lads in my Year 7 English group. But I know nothing about Peruvian snails. The small, neat cushions in Atahualpa's tank tell me he is the star of Joe's collection. It's touching, but I could do without this.
Joe is doing a project on trust for his citizenship teacher. So I have to keep his favourite pet alive for a week. I'm impressed by the handwritten booklet that came with him. It tells me that he hates curly lettuce but doesn't mind iceberg, and was named in honour of the last emperor of the Incas. His tank must always face the rising sun and I must never touch his orange crest.
Atahualpa won't survive until first break with Year 11, so the best place for him is on top of my staffroom locker. It faces an east window, and he does look splendid in the sun.
I moan about how no one trusts teachers, but this week I'm being trusted all over the place and it's alarming. Susy Dagger pounced on me at break yesterday, eyes wide with worry. "Miss Shark! I've got to talk to you about my options and whether I should stay here and do English or biology or go to St Quentin's and do music tech," she said.
I watched her spin three alternative lives in a sentence. "I want to be a drummer or a vet but my mum says I should be a journalist, and anyway English is good for lots of things but I only got a D last summer..."
Classroom doors were closing and the second bell rang. I told her to come to me in form time on Friday with a list of what she likes doing and last year's grades. Next year I want a Year 8 class.
I rang my musical friend String to see what he thought about deciding on your future so young. "What made you study physics?" I asked him.
"I had this brilliant teacher. Spiny Davis convinced me that physics was the ultimate form of music. He played us Beethoven and said, 'This is what an electron sounds like.' Amazing stuff. But I should've just done music."
I felt hot and wondered if I could avoid having a class altogether next year. I'm fine in English lessons, waving my arms and talking about life as a glittery patchwork that you sew as you go. I'm less happy when I'm put on the spot by big worrying decisions.
Now Atahualpa looks off-colour. Oh please, no. There's a smear of grey liquid on his cushion. I've put his tank by the kettle where he'll get the first rays of sun. If he just makes it through the night, then I can return him to Joe.
Young people trust me with their life choices but I can't keep a snail alive for a week. What will it do to Joe's trust in adults if Atahualpa dies? I can't think about it. I'll just have to trust him not to.
Emily's adventures continue in a fortnight