Magic Presents: Heart of the Mountain is a casual Commander event that pits players against one another as they battle for control of the Heart of the Mountain, the legendary Arkenstone. The first player to deal combat damage to another becomes the first owner of the Arkenstone. Players may then claim the Arkenstone emblem for themselves by dealing combat damage to the owner, gaining bonuses while in possession of it—and also becoming the primary target at the table!

Each turn that a player controls the Arkenstone, during their upkeep phase they increase their ownership count by one (they do not lose this count if someone takes the Arkenstone from them). If a player's ownership count reaches three, they win the game.