Here is the official summary from 4Kids Entertainment:
After the conclusion of the Battle City Tournament, deep below the sands of Egypt, an ancient evil has awakened. Anubis, who was defeated centuries ago by Yugi's mysterious alter ego -- the ancient Pharaoh -- has returned for revenge. Wielding the power of the Eighth Millennium Item, Anubis is determined to destroy Yugi and take over the world!
It's to be released on August 13, 2004.
There was also another Yu-Gi-Oh movie that was only in Japan. It wasn't really a movie though. It was only about 30 minutes (slightly longer than a regular episode) and it was about a boy named Shogo who got a Red-Eyes Black Dragon in a pack but still couldn't find the courage to duel. This movie also features that famous line:
"The
Blue-Eyes White Dragon will bring victory. However, what the Red-Eyes Black Dragon brings is not victory, but potential. There must be a
card somewhere that represents this potential. However, this is only for the one who has the courage to duel. Whether or not you find this card is dependent on whether or not you find the courage to duel."
- Old Lady