When this enchantment enters, if you cast it, shuffle your hand and graveyard into your library, then draw seven cards. The first spell each player casts during each of their turns may be cast without paying its mana cost.
原文If you cast a spell “without paying its mana cost,” you can’t choose to cast it for any alternative costs. You can, however, pay additional costs, such as kicker costs. If the spell has any mandatory additional costs, such as that of Embrace Oblivion, those must be paid to cast the spell.