Goblin Gate
Road to Rivendell #43 (x1)
Ort
5 (4)
Tor.  

While Goblin Gate is the active location, the first enemy revealed from the encounter deck each round gains ambush. If that enemy engages a player, it makes an immediate attack (deal and resolve a shadow card).

A crack had opened at the back of the cave, and was already a wide passage.
–The Hobbit