The eleventh season of the Bleach anime series, released on DVD as the The Past Arc, is directed by Noriyuki Abe and produced by TV Tokyo, Dentsu, and Studio Pierrot. The seven episode season is based on Tite Kubo's Bleach manga series. The episodes' plot follows the flashback arc of the series' storyline which retells the Visored's past.
The season first aired from February 10, 2009 until March 24, 2009 on TV Tokyo in Japan. The English adaptation of the anime is licensed by Viz Media, which has announced that this season will start airing on May 28, 2011. Aniplex collected the season in a series of two DVD compilations. The first DVD volume was released on November 26, 2009 and the second on December 16, 2009.
The episodes use two pieces of theme music: one opening theme and one closing theme. The opening theme is "Velonica" by Aqua Timez while the ending theme is "Sky Chord" by Shion Tsuji.
This episode takes place in Soul Society 110 years ago. Most of the Captains have gathered to celebrate the promotion of the 12th Squad Captain to the Royal Guard, known as Zero Squad. Meanwhile, Yoruichi (currently the Captain of Second Squad) has recommended her Third Officer, Urahara Kisuke for the now vacant position. However, Soi Fon is not happy about this and follows Urahara in an attempt to prove he is unworthy of the position. Yoruichi hears of this and mistakenly thinks that Soi Fon has a crush on Urahara. Because of this Yoruichi arranges for her to attend the Captain's Qualification Exam to watch him in action. Although Urahara, is delayed in getting to the exam because of having to capture a group of deserters he makes it in time and manages to pass. As such Urahara Kisuke is appointed as the new Captain of the 12th squad, although vice-captain Aizen Sousuke is less than pleased.
This episode is set nine years after the previous one. The 9th squad are sent to investigate after people begin to vanish from Rukongai. Whilst out on patrol Captain Kensei Mugurumathey saves a young boy from a hollow, his name is Shuhei Hisagi. He then discovers that 10 of his own men have also vanished and calls for the Technological Research Bureau to help in the investigation. As such Hiyori is dispatched.
An emergency is declared following the attack on the 9th Squad. Captains Shinji Hirako, Love Aikawa and Roujuurou Ootoribashi are dispatched to investigate along with vice-captain Lisa Yadomaru and Hachigen Ushoda from the Kidou Corps. When they arrive they discover Hiyori fighting with a 'hollowfied' Kensei and soon a 'hollowfied' Mashiro also appears. Meanwhile, Urahara and Tessai Tsukabishi (Captain of the Kidou Corps) disregard their orders and also head out to investigate.
Shinji's group manages to restrain Kensei using a powerful Kidou spell but then Hiyori also undergoes 'hollowfication'. They are then attacked by Tousen and as the rest of the group undergo 'hollowfication' Shinji battles against Aizen and is almost killed when Urahara and Tsukabishi arrive to save him.
Urahara confronts Aizen about his hollowfication research but ultimately Tsukabishi is unable to capture him. Meanwhile, after being transported back to the 12th Squad headquarters Urahara decides to use Hougyoku to save Shinji and the others. Urahara and Tsukabishi are then arrested by Central 46 and blamed for the hollowfication experiments. However, before their sentences can be carried out Yoruichi appears and helps them escape to the real world.
In the Soul Society 110 years ago, the Thirteen Court Guard Squads are made up of unfamiliar faces. The captain of Squad Five is the masked Visored, Shinji Hirako who currently resides in the World of the Living.
Kisuke Urahara replaces the newly promoted Kirio Hikifune as captain of Squad Twelve. Hiyori Sarugaki, lieutenant of Squad Twelve, cannot hide her dissatisfaction with the new captain.
Kisuke takes Hiyori to the Special underground Confinement Unit inside the Squad Two barracks. Nicknamed the Maggot's Nest, this place imprisons enlisted Thirteen Court Guard Squad members whose beliefs or actions have been deemed dangerous.
Nine years have passed since Kisuke Urahara was appointed captain of Squad Twelve. Bizarre deaths start to occur in the Rukon District where people disappear, leaving only their clothes behind.
Kensei Muguruma's and Mashiro Kuna's Spiritual Pressure disappears. The Seireitei deems this a dire situation. Kisuke Urahara, who sent Hiyori to Squad Nine, volunteers to go to the scene of their disappearance.
At Squad Nine's camp, Shinji Hirako and the others run into Kensei Muguruma, who is donning a strange mask. Kensei starts to attack them, and he is too powerful to stop even with all of them combined.
Sosuke Aizen suddenly appears in front of Shinji Hirako and the others. He draws his sword on Shinji, who is agonized by his Hollow transformation and cannot move his body at will.