Counter-Spell
Shadow and Flame #145 (x3/x1)
Traición
Shadow.  

When Revealed: Attach Counter-Spell to Durin's Bane. Counts as a Condition attachment with the text:

Forced: When a player plays an event, discard the top card of the encounter deck. If that card is a treachery card, cancel the effects of the event, discard the event player's hand, and discard Counter-spell from play.