Shadow, Sky Runner's little sister, is one of the best little burglars in Canterlot. Every Hearth's Warming Eve, this little tomboy pegasus puts on a disguise and slips out into the night to enact some kind of strange yearly ritual without her sister's knowledge. She changes colours, puts on a different cloak and runs off to do who-knows-what! Sky, being as she is a nosy bint, follows her this year to investigate. The truth of Shadow's little ritual might not be what she's expecting.