In UNDO - Long Live the King, players learn the rules and encounter the starting situation of the case on the first few cards, which also guide them through the setup. Once the setup is complete, players carry out nine time jumps. Every jump takes them to one independent moment from the past and allows them to change that moment in one of three ways, which may change the starting situation for better or for worse. The players need to discuss what they know and try to come up with theories about the story, using the clues they gather from the different time jumps. Only by continuously adapting their theories and making the right choices will they successfully change fate and save the life of the king.