With time running out and Obi a ticking time bomb, someone must take matters into their own hands to save everyone.
With the world watching the telecast, the Beam Amanto reveal that Earth has twenty four hours before the implanted beam cannon fires, sparking a galactic war, unless the Earth's government reverse their stance to make beam cannons illegal. They also add that the "present" has a self-defense system that will destroy the planet if anyone tries to stop it. Gengai tells Gintoki that the planet Beam is a weapons manufacturer but don't get involved in politics. Yet there is a radical sect named Firestarters who like to create wars and that Obi is most likely a false hero created by them and might not be aware. Meanwhile, machine Obi encounters Shinpachi before quickly returning to normal and the two males decide to exercise. Gintoki asks Gengai of a way to stop the cyborg while Tae quietly listens outside. At the same time, the Shinsengumi and the Yagyuu clan prepare to search for the cannon and build a shelter for the Shogun respectively. Kondou and Kyuubei come to the realization on what, or rather who, the Firestarter's "present" is.
In the late afternoon, Obi and Shinpachi take a bath in a bathhouse with Kagura monitoring the temperature; Gintoki watches through the door and wonders where the cannon is hidden. Gengai had given him a special katana that will temporarily disable the self-defense system so Gintoki can destroy the machine half. He reiterated that Gintoki cannot save Obi. Tae arrives to ask about Gintoki's presence near the bathhouse and the silver haired man responds with the truth, he's here to kill Tae's first love and admonishes her for eavesdropping. Shinpachi washes Obi's back and admits that the cyborg was still so strong, like in the past. Obi responds that Shinpachi is stronger as he feels so hollow despite becoming a Sword Master, realizing that true strength comes from protecting those close to you and wishing that he visited Japan sooner. Shinpachi angrily berates Obi for giving up, making him realize Shinpachi knew who he really was. Tae tearfully pleads to Gintoki to let Obi live just a little longer so she and her brother can have their brother figure again. Shinpachi sadly laments his wishes that if it wasn't for the bomb, he would have been happy to see the interaction between his two brother figures, Obi and Gintoki.
Obi admits that he was going to kill himself since he could no longer restrain his machine side but he wanted to see the Shimura siblings one last time (unbeknownst to Shinpachi, at this moment machine Obi took over). Before "Obi" continues, Gintoki stabs him in the mechanical side of his chest, horrifying the siblings and Kagura. Shinpachi tries to stop him but is thrown in the bath and the distraction allows "Obi" to escape. Shinpachi demands to know why Gintoki was attacking; Obi knew and understood what was going on and was going to end this himself. Gintoki merely answers that Obi's body was not his own and that the siblings were being sentimental over a corpse. He adds that he will save the world and finish the job of killing him before leaving. An enraged Shinpachi rushes to hit Gintoki but it results in Gintoki slamming his head to a tree. Shinpachi wonders why his big brother figures are so different but Gintoki coldly remarks that he was never big brother material in the first place then leaves. As Tae and Kagura tend to Shinpachi, people arrive to the household.
Machine Obi, Kenofi, notices that his self-defense system wasn't activating while hopping rooftops in escaping. He realizes that Gintoki had done something when he attacked Kenofi when he sensed the cyborg's killing intent to Shinpachi. Some of the Shinsengumi, lead by Yamazaki, find him and Kenofi flees, the shouts notifying Gintoki. Back in the Shimura residence, the Shinsengumi and Yagyuu school search throughout the house for Obi. Shinpachi angrily yells at the overseeing Hijikata and Toujou for taking advantage of the Obi manhunt to dispose their respective bosses' love rival. The two tell the siblings and Kagura that the person who asked them to be here wasn't Kondou or Kyuubei, but Gintoki. In a half constructed building, Kenofi tries to contact his masters but is interrupted by an explosion made by Gintoki breaking through a wall. Kenofi admits that he had underestimated Shinpachi's new brother figure but Gintoki responds that he and the younger Shimura are not interested in being brothers before attacking him with the sword. Okita interrupts Hijikata to tell them that the regular police were now outside the residence. As Toujou and Hijikata stall them, Okita reveals that Gintoki had begged, on his knees with his head bowed, the two groups to protect the Shimuras and Kagura, foreseeing that they may be targeted due to their connection with beams, while he deals with the cyborg. Shinpachi demands to know why but Tae answers that the samurai was the only one determined to bring Obi back, shocking Shinpachi.
At the same time, Kenofi taunts Gintoki about their fight, knowing that if Gintoki kills him, he will lose the trust of his friends and wonders why he continues. Gintoki answers that he would much rather fight and die than be sentimental. The cyborg mocks the samurai's statement before creating another beam sword with his robotic arm and strikes, knocking Gintoki into the wall. He tells Gintoki that the human had been subconsciously ignoring the cyborg's human side. Gintoki mocks Kenofi's "Sword Master" title and tells him the title of "Big Brother" fits better. He adds that no one will help the both of them and asks Obi to come back. Kenofi answers by using his beam sword arm to strike Gintoki through the floor, adding that Obi can't come back. He contacts his masters again to be picked up. But the radical Beam Amanto in their hovering space ship state that they had already retrieved him. Just then, the transporter explodes and Gintoki appears behind Kenofi and strikes. The teleporter contains Kyuubei and Kondou and Kenofi realizes that Gintoki had also disrupted his transmitter. He, along with Shinpachi and the girls, learns as well that Gintoki fighting Kenofi was also a distraction as the Shinsengumi work to disable the cannon, surrounding the ship. Gintoki gleefully repeats that no one will help them and demands that Kenofi leaves Obi's body. Enraged, Kenofi attacks.
In the enemy ship, Kyuubei and Kondou are surrounded by the Firestarter faction. Kondou admits that helping their rival in love won't gain them anything and Kyuubei adds that they had it better than Gintoki, who threw away his pride to ask for help and will lose his brother figure status if successful. She also understands how Obi was responsible for Tae's tendency to smile even when things were sad or painful and just wants Tae to be happy again; Kondou agrees and the two fight. Okita watches the siblings and Kagura leave towards the fight, stating that little brothers' have pride too. Toujou and Hijikata agree, stating that they should go to their respective big brothers, too. Back on the ship, the swordsmen defeat the faction but the leader mocks them as they will be unable to keep Obi alive due to the time limit of the temporarily disabled self-defense system. Kondou angrily yells at him to return Shinpachi's big brother figures. In the construction building, Kenofi walks towards a defeated Gintoki, telling him that his systems will come online in thirty minutes and the only way to stop his beam cannon is to kill him. He tells Gintoki that his "little brother" and the planet will follow and readies a blast to kill him. Instead, Gintoki is saved by Shinpachi, who slices off Kenofi's mechanical arm and tells him that he and Gintoki are not brothers.
- Sakata Gintoki
- Shimura Tae
- Shimura Shinpachi
- Obi Hajime
- Hiraga Gengai
- Yagyuu Kyuubei
- Yagyuu Binbokusai (cameo)
- Yagyuu Koshinori (cameo)
- Toujou Ayumu