You are playing Nightmare mode.

Setup: Set both copies of Mûmak Elite aside, out of play.

Forced: When quest stages 2A or 4A are revealed, add 1 of the previously set aside copies of Mûmak Elite to the staging area.

For a moment he caught a glimpse of swarthy maen in red running down the slope some way off with green–clad warriors leaping after them, hewing them down as they fled. Arrows were thick in the air. –The Two Towers

Begin with the standard quest deck and encounter deck for the Into Ithilien scenario.

Remove the following cards, in the specified quantities, from the standard encounter deck:

1x Blocking Wargs

2x Watcher in the Wood

3x Secluded Glade

3x Forest Bat

3x Southon Mercenaries

1x Overgrown Trail

Then, shuffle the encounter cards in this Nightmare Deck into the remainder of the standard Into Ithilien encounter deck.

Finally, flip this setup card over and place it next to the quest deck. Its effects remain active throughout the game, which is now ready to begin.