What is the plot of Yu-Gi-Oh?

Yu-Gi-Oh! is about a boy named Yugi Mutou who plays a card game called Yu-Gi-Oh! He solves the Millennium Puzzle so his body now hosts the spirit of a gambler as well, and takes on various challenges against enemies. Most often, the challenge is the Yu-Gi-Oh! card game but sometimes it will be alternate games such as dice or board games. As the show moves forward, Yugi and his friends discover the spirit is actually an Ancient Egyptian Pharaoh with amnesia so they try to help him regain his memories by facing additional challenges from gamers with Millennium items.