Advance Warning

Event. Cost: 2.

Play only if each hero you control has a printed resource icon.

Action: Until the end of the phase, enemies do not make engagement checks.

Suddenly he halted and listened. Had he heard a whistle or not? Or was it the call of some strange bird? The Two Towers
Adam Lane

The DrĂșadan Forest #40. Lore.

Advance Warning

If you can afford to play this card in a Fellowship with an high player count this is basically one the best cards possible for a mono-Lore deck. Being able to avoid all enemies except those that you want to engage (although to a limit of 1 per player) is worth its weight in gold, especially since you can re-use this card for quite cheap with a Scroll of Isildur.

I also think it's worth noting that it's an Action not restricted to the Encounter Phase, so if you find yourself in one of those few quests where you are forced to make engagments checks outside the Encounter phase (and you have an available Action window) it can still be quite powerful to use.