There have been numerous questions about how some of the new cards work. Here are some of the more commonly asked questions.
Nephthyria, Solemn Jailor’s ability lets it serve as a counter against aggressive play, preventing cards like Hrist of the Infernal Blades or Ferocity Unleashed from playing out cards other than from hand. However, the original printed text was not sufficiently clear on what Nephthyria, Solemn Jailor is able to prevent.
And so, we have changed the text to better reflect how the ability works
CONT@ All players can only play spells or summon creatures from their hand. (Spells and abilities that play spells or summon creatures cannot be used.)
Fort bursts and ambushes can still be able to be activated, as players are not playing the ability, not the card itself. However, if the ability’s effect includes the playing of a spell or the summoning a creature, that part of the ability would be prevented by Nephthyria, Solemn Jailor.
The next question is tricky one that requires a look at the comprehensive rules. With Serene Prelate in play and Restrain in effect, what would the cost of placing an ambush be? The answer lies in the order that their effects are applied, and in section 188.8.131.52 of the comprehensive rules, we can see that abilities that set numeric values will be applied before abilities that modify numeric values.
And so, Serene Prelate will first set the cost of ambushes to 0, followed by Restrain’s effect to increase the cost by 3, resulting in a final cost of 3.