When playing Promising Future with Lux Champion, if you reveal and play another 5-cost spell from the top 5 cards, when do you draw cards from Lux's ability?

Ruling: When you play Promising Future, the cards chosen from it are put on the pending chain first, then Lux's ability trigger is added to the pending chain. When cards move from pending chain to the chain, the 5-cost spell from Promising Future goes on the chain first, then Lux's draw ability resolves. If that 5-cost spell is also a spell, it triggers Lux's ability again after it resolves.

Sequence:

• Play Promising Future
• Cards from Promising Future are put on the pending chain
• Lux's ability trigger is put on the pending chain (last)
• Cards move from pending chain to chain
• The 5-cost spell from Promising Future goes on the chain
• Lux's draw ability goes on the chain and resolves
• The 5-cost spell resolves
• If it was a spell, Lux's ability triggers again after it resolves