War of the Spark contains 264 cards (15 basic lands, 101 commons, 80 uncommons, 53 rares, 15 mythic rares), and includes randomly inserted premium versions of all these cards.

The storyline and set revolves around the fight between the Gatewatch and Nicol Bolas. The fight turns into an all-out planeswalker war.

Dozens of powerful planeswalkers, from many disparate realities, unite against the elder dragon, who has claimed dominion over Ravnica and is perilously close to completing the Elderspell that harvests sparks and will grant him «ultimate power» and godhood.