Auld Lang Syne: Cat and Mouse is a visual novel made in RPG Maker VX Ace. It's a Granblue Fantasy fangame about two Zodiacs of many years in the past. You don't need to know much about Granblue Fantasy, only that its setting is a world of floating islands with its own fantasy races, and that there's a group of characters inspired on the Chinese Zodiac/the Twelve Divine Generals. With the exception of the minor NPCs and Dormouse, it's all original characters and story.