From the website:
This card game is about kitsune who play tricks while scheming to punish mortal fools for their foolishness, sometimes teaching them a lesson in the process. By correcting mortal foolishness, the foxes earn their tails. Each player takes the role of a fox trying to earn his or her tails through impressive schemes. Some cards represent the foxes; others, the tricks they can play in their schemes, the fools to whom they must teach lessons, and the consequences that befall foxes who fail.