Dol Guldur as seen in the films
Sauron settled in Dol Guldur as the Necromancer
Radagast briefly battled the Witch-king in Dol Guldur
Dol Guldur is depicted as a huge, decaying castle set on top of a hill. Radagast the Brown enters the fortress to investigate the evil force within. He briefly battles the Witch-king of Angmar who is shown unclothed and in full spirit form, before glimpsing the Necromancer. He flees to tell Gandalf of what he saw.
Sauron, as the Necromancer, began gathering legions of Orcs for war in his refuge
Gandalf confronted and uncovered the Necromancer as Sauron
After imprisoning Gandalf, Sauron unleashed the armies of Orcs
Gandalf and Radagast went to Dol Guldur to uncover the Necromancer
After leaving Bilbo and the party of Dwarves, Gandalf seeks the tombs of nine servants of Sauron (who were the bearers of the nine rings of power gifted to the race of men) located in the High Fells of Rhudaur. The tombs of the Nine Ringwraiths were open, showing that they had been summoned from the dead. After this discovery, Gandalf convenes with Radagast in the High Fells, learning that the Nine have departed to Dol Guldur, answering the call of the Necromancer. He and Radagast then travel to Dol Guldur to investigate further and confront the evil which dwelt there. Gandalf performs revealing spells that remove the illusion displaying the castle as abandoned and ruined. In the Extended Edition, Gandalf finds Thrain there and helps him escape. Gandalf and Thrain are then attacked by Azog (and a few of his servants) who reveals his hordes of Orcs and Wargs inside the castle preparing for war. Gandalf then uses his magic to escape Azogs grasp, but the Necromancer manifests at Dol Guldur's exit. The Necromancer sucks Thrain in and kills him. The two then start a battle of light and shadow until The Necromancer defeats Gandalf, destroys his staff, and then reveals himself as the Dark Lord Sauron. Gandalf is later seen trapped in one of the cages of the castle watching the vast hordes of Sauron's armies leaving Dol Guldur.
Galadriel came to rescue Gandalf from Dol Guldur but was halted by the Nine
Elrond arrived in Dol Guldur to aid Galadriel shortly before Saruman
Radagast arrives in Dol Guldur while Saruman and Lord Elrond fend off the Nine
Sauron threatens the White Council of the fall of the East and Angmar's rise
Galadriel, Elrond, and Saruman are seen gathering at Dol Guldur to face Sauron and the Nine Ringwraiths. Galadriel keeps her promise made to Gandalf in the first Hobbit film and comes to his aid in Dol Guldur. In the extended edition, a large orc is seen throwing Gandalf around. Gandalf then attempts to defend himself grasping a loose chain and striking the orc with it. The orc, unfazed once again grabs Gandalf. The Ring of Fire, Narya is then seen by the said orc. The orc without hesitation gets ready to cut off Gandalf's arm. Momentarily Galadriel reveals herself and states "I come for Mithrandir, and I will leave with him. If you try to stop me, I will destroy you". The orc in defiance shrieks at her. With the power of her Ring of Power, she with ease blasts him to pieces, causing light to "ride" the clouds for miles. She then carries the unconscious Gandalf to safety, but as she does such, Sauron summons the Nazgûl. Galadriel is horrified by the sight of them. Sauron proceeds to taunt her for being alone, Galadriel proceeds to state clearly that she indeed isn't alone.
After defeating the Nine, the White Council was confronted by Sauron
After the Nine's defeat, Sauron was banished by Galadriel in her spectral form
After Sauron was banished, Elrond was ordered to take Galadriel to Lothlorien to heal
Elrond arrives on the scene, drawing his sword. Saruman, appearing shortly after Elrond, witnesses the Nazgûl with his own eyes, realizing he was wrong to doubt Gandalf's claims. Shortly thereafter Elrond strikes defeating a few of them, Saruman then entering the fray. While the two of them are locked in a fierce battle with the Nazgûl, Galadriel heals Gandalf with a kiss. When he comes back from the dead, he and Galadriel acknowledge that Sauron has once again, returned. Radagast then arrives in Dol Guldur to take Gandalf to safety, but he is hesitant to leave Galadriel's side. Gandalf also insists Galadriel should come with them, but Galadriel suddenly enters a trance and forcefully commands Radagast to leave with Gandalf. Radagast, terrified does as such.
When Sauron manifests before them, Saruman cowers in fear as Galadriel takes on a terrifying and corrupted image, challenging Sauron, and banishing the Nine almost instantly. Sauron attempts to sway her to his side, but she denies him. Galadriel's power eventually overrules Sauron, and by her efforts, Sauron is banished from Dol Guldur, his spirit fleeing back to Mordor. Elrond escorts Galadriel to safety after her struggle with Sauron on orders from Saruman, while Saruman himself is tasked to deal with Sauron. This was later revealed as an excuse for him to search for the One.