There are 2 groups during game playing: a player plays as Katy and others play as rats. If Katy catches all the rats, Katy wins. If rats get a big cheese together or some selfish rats get cheese alone, rats win.
There are 4 phases in a round:The Sleeping Phase of Kitty, The Running Phase of Rat, The Running Phase of Kitty and The Tool Phase of Rats.
If Katy or Rats gets the Goal of the game, they win immediately.