Eye of the Moon Plan

The is Madara Uchiha's ultimate plan to create an idealistic world, which was later adopted by Obito Uchiha. With the Allied Shinobi Forces seeing this as nothing more than robbing humanity of their free will, they intend to foil this plan. This led to the declaration of the Fourth Shinobi World War.

The Plan
Madara created the plan by studying his distant ancestor, the Sage of Six Paths. He resolved to gather the nine tailed beasts and merge them with the Demonic Statue of the Outer Path in order to revive the Ten-Tails. Then, he would become its jinchūriki and use its god-like power to reflect his Mangekyō Sharingan on to the moon, the prison of the Ten-Tails' body, and shroud the world in an. This scheme would result in Madara's ability to manipulate every living being, ceasing all conflict by purging free will itself from the world.

Due to his poor health condition, Madara could no longer work on the plan at some point, and left its completion and his will to Obito Uchiha. Obito would then engineer the formation of Akatsuki, though most of its members were unaware of the organisation's true objectives. By creating the alias "Tobi" and posing as Madara, Obito ensured that Nagato, the figurehead of Akatsuki, would revive Madara with the Outer Path: Samsara of Heavenly Life Technique when the plan finally came to fruition. Nagato believed they were collecting the tailed beasts to create a dominating power that would carve the way to peace. Obito's personal reasons for the Eye of the Moon Plan is to remove the agency of all living creatures and create a reality where Rin is alive so they can be together once more. He had also approached Kisame Hoshigaki, requesting is participation in the plan with the offer of freeing him from the "world of lies"; Kisame, having lived a life tainted with deception and betrayal, gladly accepted to the "world of truth" he desired, and along with Obito and Zetsu, become the only Akatsuki member to know the truth of the organisation's goal.

Progress of the Plan
Though Obito obtained seven of the nine tailed beasts, only the final two tailed beasts: the Eight and Nine-Tails, remained out of his grasp. After Nagato's death ruined any chance of Madara's resurrection, Sasuke Uchiha's failed attempt to capture Killer B provided him with a fragment of Gyūki's tentacle. Obito decides to take Madara's place in the Eye of the Moon Plan. Discarding all caution and revealing himself through his Tobi guise, Obito arranged to place Sasuke and his team at the Kage Summit in hopes the ninja leaders would be weakened enough to be easily taken hostage to negotiate their freedom in exchange for the last two living jinchūriki, Killer B and Naruto Uzumaki. This, however, ended in failure, due to Danzō Shimura escaping during the chaos while combined forces of the Kage, their bodyguards, and Mifune overwhelmed Sasuke. Sending Sasuke into the other dimension with Karin, Tobi introduces himself as Madara while revealing this plan to the four Kage. However, they refuse to hand over Killer B and Naruto while forming the Allied Shinobi Forces to prevent Tobi from going through with his Eye of the Moon Plan.

At the end of the first day of the Fourth Shinobi World War, Tobi took the Kohaku no Jōhei and Benihisago that each contained one of the Gold and Silver Brothers, and having already fed the Eight-Tails' tentacle to the Demonic Statue, Tobi intends to put the plan into motion by the end of the following day. Later, while fighting Naruto by the time that his true identity is eventually exposed by both Madara's return through Kabuto Yakushi's Impure World Reincarnation and his younger opponent shattering his mask, Obito fed the Kohaku no Jōhei and Benihisago to the Demonic Statue in order to revive an incomplete Ten-Tails, claiming that the monster would still have enough power to be sufficient in completing his plan. Once joined by Madara after he defeated the Kage, Obito is scolded for deviating from the original plan due to the Ten-Tails' revival being incomplete and his own revival through a different method. Regardless, entrusting Obito to make sure no one interferes as he battles Naruto and Killer B, Madara decides to capture the Eight and Nine-Tails personally to complete the plan while there is still time.

Trivia

 * Obito has blamed Naruto for the plan's slow progress, due to his constant interference causing him to deviate from the plan as Madara envisioned, despite the plan would eventually involve capturing Naruto.
 * Obito noted that he would eventually synchronise Sasuke Uchiha with the statue.