Set sometime after the main story.
The story start as Shidori awake from her bed as she prepare for Kagura ritual dance. During the rirual, she heard a bell that ringing around her which interrupt her dance. As the result, she went back to her room and hear the bell again. But this time, a bright light of a tiny tome is come near her. As she touch it, she witness all memory of herself at rapidly which cause her to passed out as Nana and several servant try to awake her up. As Shidori find herself in the dark place, a bright tome ask her to follow the portal where her memory was. After Shidori enter to the portal, all flashback were show.
Following the death of Rinne's last friend, Kibori. Rinne live in the house with Rio until she passed away following a car accident following a truck crashing into her, left Rio orphan and adopted by Dinogi family. After Rinne died, she once again meet Chitose in the afterlife were she become a god. After three universe has complete and sge is about to create the fourth universe. She meet Kibori, and later, her husband Shido, who died as attempt to save her from Nill William back in 2017. As both has family reunion, Rinne find Shido has heart egg that about be hutch. She use her power to create Shidori who once to be part of his body is no longer shared same body and now different but has retain same memory as him. However, Shidori didn't know Shido and her were same. As Rinne is create a new universe, she wish everyone to see everything Rinne have done to the universe before the next universe is complete. As everyone is prepared for visit other universe. Rio has whisper Shidori saying to find most important thing that Shido is looking for.
There, Rinne and the group has viewed all the event prior the new beginning of the Gamalaticania Universe including the Negative One where Lowee Empire's full scale invasion on Neutral Alliance capital, Cheyenne City where Lady Blanec crush and burn them to ground with Section 39, and Koto Mura where Kotora's sacrifice to blow up the Great Mind Trick while Kotori is fighting against Georcas William. As Rinne said his name William, Shidori was shocked as it remind her to someone like Nill William. Rinne has warn everyone not to tell his name as it could corrupt someone and let him escape. Shidori witness the event that Blanec has died, and Kotori almost die by Georcas but save by mystery tome which overcome the weakness. Shidori question Rinne about the tome that save both Blanec and Kotori as Rinne is hide something from her. Rinne answer there is nothing as tome exist as Shidori find to be shocked to hear from Rinne but still not accept her answer as conclusion.
As Shidori has done her question, every soul has visit Reva Hana, but before they enter to that universe. Everyone is stop by to the deepest place where the remain of Nill William's existence was imprisoned to the place that can't be reach and can't heard. As Rinne explain he is nothing more but shattered mind twisted that no lifeform or god can understand his suffer, or he either as any being attempt to see or heard his sound could die even in this sprits form. However, Shidori hear his voice and witness his mind and suffer where he is nothing more but punished by his own action and crime in the past where he once done for the ABM group. As Shidori see, his action is getting worse where to the point that nothing is achieve but his endless desires that bite him to dust. Shidori almost end up kill herself in this afterlife as if Nill William is mind control her. Rinne saw Shidori witness Nill William's sins and is about to kill her, everyone come to save her from getting corrupt by him. Rinne glad that Shidori has survive thanks to her strong will to understand as not all people witness his crime and whoever contact his mind is not end well.
After other has watch the timeline of the Reva Hana's first part where they saw Sakura and Ringo's experience and the destruction of mankind by Chiyome. Both Shido and Shidori saw a bathtub block their way and never let them pass without bathing. In order to overcome their fear, they decide to take a bath together to confess their feel and fear they hiding in past life. As both looking each other in the tub as they talking to something they admit they can't accept about Rinne and her childhood friend, Kotori. Shidori question on most important thing that Rio is looking for these year is finally revealed to be good family with Shido. Shido told that it might be for Shidori after all as his trauma in the past as Rinne face with Nill William and the ABM while he protect her. Shidori heard something that he mention about saving Rinne as she wish she want to live free in next life as shine as princess. Shido don't want her gone from his side and stay with Rinne and Rio as next world is cruel for pure soul to be go but he can't against her if this is her wish as every soul has one wish before can either live with her or send to new world to be reborn. After Rinne and the other notice that both Shido and Shidori is missing, they head back to find out that both are naked in the bathtub. Both Shido and Shidori who see each other admit their confess that they wont shy away from bathing together. As Rinne smile on both to be brave to do such thing as bathing, Shidori ask will she want to take a bath with Shido and her which Both Shido and Rinne refuse immediately.
After the bath as they miss a lot of Reva Hana universe story, they finally decide to head on to final timeline where Rinne witness her own death in her past life where Rio couldn't save her and crying of seeing her mother's death. Shidori hug Rio and cry as well as she don't want to see people suffer by other's desire or has terrible fate because of other people change their fate. Shidori notice that Rinne being transform into a light that same one as mystery tome as Rio look her sprits which reveal to be Rinne herself is behind all this, but she couldn't remember it as it happen at fragment of memory of strong will to see. Rinne admit it was her all along as she try to hide it from her as she don't want to see someone lose to the impossible threat that universe don't want to see. Rinne then reveal that Shido didn't died try to save her, but it was Shidori all along as Nill William kill her as she attempt to save Rinne from her death which is the reason why she experience something nobody saw. Shidori cry as Rinne and Shido didn't talk about her death which also took Shido within. He hug Shidori as he wish she have a better life if she want to be born in next life.
In the end, Rinne is farewell to every soul who wish to be reborn in new world. Shidori, who is no longer connect to her counterpart Shido decide to going to new world as promise her counterpart Shido to take care of Rinne and Rio before finally say goodbye to the old world and the afterlife. But before she depart from afterlife, she saw both Kotori and Mayu looking on her while she ask why Kotori and Mayu go to see Rinne. Kotori just response that she can't see anything and confuse who is she talk to as she can't hear Rinne's name. Rinne also can't see or hear Kotori's name either. This imply that both world is forever lost as Kotori is graduated from her world after she find her mother, both Kotori and Rinne wish one day will reunited with Rinne if they meet again, which Kotori say that her strong will would bring back both together.
As Shidori is finally born as Shrine Maiden in the Imperial Hana Palace where she was Princess to the Hanasawa Empire. She thank to Rinne and Shido, as well as everyone to give her next life where she will find as her ultimate test as Shidori finally awake up from her passed out, making everyone relief as they thought she death.
