In the original Battle for Middle-earth, the Campaign follows the plot of the Lord of the Rings movie trilogy. There are mandatory missions, and lands that the player can choose to attack. Unlike the films, Gandalf is able to survive the conflict with the Balrog, Boromir his battle with the Uruk-hai, and Theoden his confrontation with the Witch-king at the Pelennor Fields.
The Good Campaign follows first the journey of the Fellowship through Moria and the war between Isengard and Rohan, with Eomer as the player's primary hero against the orcs of Saruman. Following the battles of Helm's Deep and Isengard (both mandatory missions), the War turns to Gondor, where Faramir most often leads the player's troops. All heroes then appear at the Battle of Minas Tirith, after which the player can either end the Campaign by assaulting the Black Gate, or attack other regions controlled by Mordor, such as Rhun or the Dead Marshes.
The Evil Campaign opens with the betrayal of Saruman and his War on Rohan. The player must attack and conquer Fangorn to kill all the Ents before assaulting the Fellowship at Amon Hen (as took place at the end of the Fellowship of the Ring film). Once Rohan and all its armies fall, Mordor must secure the loyalty of Evil Men before making war upon Gondor and destroying its cities and soldiers. The campaign ends with the conquest of Minas Tirith, at which all surviving heroes die.
In BFME II, the player can play and progress in both The Good Campaign and The Evil Campaign. Both campaigns have eight stages, and describe the events that occurred in the North (specifically, a war between the Elves, alongside the Dwarves, and the forces of Goblins and Mordor) during the time of the Fellowship of the Ring's quest to destroy the One Ring in the South.
The good side of the storyline focuses on Elrond and Gloin's planning and organizing of the War in the North. The game starts out as the hero Glorfindel discovers an attack to be focused on the Elven city of Rivendell. Due to the hero's warning, Elrond is able to rally his army into the Elven sanctuary in prepare for the oncoming Goblin attacks. Elrond is able to destroy and rout the Goblins, for an Elven victory.
Following the battle, Elrond discovers that he must join forces with the Dwarves in order to win the raging war. These events spark the beginning of an alliance and a friendship.
The evil side of the storyline displays the alternate side of the War in the North. The Dark Lord has assigned The Mouth of Sauron and the Nazgul to rally the Goblins inhabiting the Northern part of the province. The evil lieutenants lead the Goblin army to Lorien, and, despite heavy resistance, destroy the forest.
This leads to Gorkil the Goblin King's Goblins and the Evil lieutenants amassing a great goblin army to combat the Good forces in The War in the North.
BFME II: The Rise of the Witch-kingEdit
In The Rise of the Witch-king, only one campaign is available: that of the conquest of Angmar. This tells an entirely new story, where the Witch-king tries to amass an army to conquer the free peoples of Arnor.