So I just so happened to read this before Christmas, and turns out it was a Christmas story in the Enderverse. It deals with Zeck, who comes from a very religious family, a Puritan one, who rejects electricity and certainly Christmas as from the devil. But Zeck is a genius, he has a perfect memory, and can make people like him. So when he goes to Battle School he causes a bit of trouble.
Zeck ends up in Rat army with Ender, but Zeck refuses to play the IF’s game, so he never shots anyone. Everyone else hates him because he does nothing and refuses to be apart of it all. This is his attempt to be sent back home.
The real trouble starts when Dink sees a fellow Dutch boy put out his slippers on Sinterklaas eve, and he goes ahead and puts a gift, a poem, inside. Zeck decides to rat on them for religious activities, which are prohibited in the school. But Dink fights back and causes the whole school to start giving gifts from Santa, who is not religious. And the school does nothing, which infuriates Zeck, who then subtly makes the Muslims decide to start praying again (they had been given an exemption from daily prayers, apparently), it is then Graff steps in and stops it.
And so Zeck is now completely ignored and hated all the more. And of course, it is Ender who comes to the rescue and gives him a working and gets him to realise the truth about his family, and the father he looks up to so much.
The story was short and interesting enough to see another experience of the Battle School and how it operates.