The Lord of the Rings: The Fellowship of the Ring
The Fellowship journeys to the Gap of Rohan, but discover it is being watched by birds (of a species known as "Crebain") who spy for Saruman. They decide to walk through the mountain pass of Caradhras instead, but Saruman uses magic to create a storm. The Fellowship is forced to travel through the Mines of Moria, a mine which used to belong to dwarves. They find out the dwarves there are dead. They are then ambushed by a lake monster. The entrance collapses, trapping them inside. Pippin ends up accidentally awakening the orcs in the mines, leading to a battle. They also kill a cave troll during the battle. The Fellowship then begins running from the orcs, but the orcs flee when an ancient demon known as a "Balrog" awakens. Gandalf saves the Fellowship from the Balrog, but sacrifices himself in doing so.