Odyssey's theme is the graveyard. All the colors interact with the graveyard and use it as a resource. Previously, the graveyard rarely affected gameplay, but Odyssey's cards forced players to constantly keep track of both graveyards at all times.

The storyline of Odyssey leaps forward 100 years in the future on the remote continent Otaria. Odyssey 's protagonist is Kamahl, a formidable fighter-mage skilled in both magic and melee combat. Kamahl has a close friend Chainer, a cabalist, and a cool-headed sister Jeska. The antagonist is Laquatus, a sly merfolk who uses trickery and mind control to bend others to his will. Almost everyone in the story is after the Mirari, a legendary artifact of immense power with the ability to make its wielder's innermost wishes come true. The Mirari is relatively small, resembling a metallic ball mounted on a wirey helix.

Odyssey introduced two graveyard-centered mechanics:

• Flashback - These spells can be played again from the graveyard, essentially getting a second use out of the spell. However, using a Flashback ability removes the card from the game.

Red and green are the strongest flashback colors.

• Threshold - Certain spells and creatures gain bonuses when your graveyard reaches or exceeds the seven card threshold. Blue is lacking in threshold cards but has the easiest time achieving threshold.