Sento: A war has broken out between Touto and Hokuto over the immense energy within Pandora's Box. Kamen Rider Build, Kiryu Sento, decides to risk his life defending Touto from Hokuto's Kamen Rider Grease and his three lackeys.
Misora: HI! It's Miitan, your idol!
Sento: What's with you?
Misora: My request today...is that the war stops, right now!
Kazumi: We'll stop! If that's what you want, Miitan! Then again, Grease hasn't really had much of a spotlight yet.
Sento Okay, here's episode 20.
Beat: The upbeat mood of Kazumi's forgiveness and the Crows carrying them ends as Sento and Ryuga unexpectedly crash their moment and everything drops. The four try to regain their battle persona before they transform.
Call-Back: When Sawa and Misora undergo disguises as nurses to cure Taizan Himuro, the guards watching him in the hospital return as the same ones from #12. One specifically recognizes Sawa as the woman who kicked their butts and escaped. This time, she knocks them away and prevents them from interfering with Taizan's recovery.
Curbstomp Battle: Night Rouge vs Build. Gentoku couldn't lay a hand on Sento at all, and lost Pandora's Box.
Death of Personality: Unlike the Smashes, Soichi warns Sento that prolonged use of the Hazard Trigger would cause Sento to lose his sense of self.
The Exile: Taizen expels Gentoku from not just the government, but Touto as a whole!
Freeze-Frame Bonus: In a brief second, the audience can see the real names of the Hokuto trio. Akaba's real name is Ooyama Masaru, Aoba's is Syuuya Aikawa, and Kiba's is Syoukichi Mihara.
Finishing Move: Night Rogue attempts a new finishing move where he wraps his wings around him in mist and delivers a spinning Diving Kick. Unfortunately, Sento stops his attack with one hand and defeats Gentoku with his Sparkling Finish.
Hope Spot: Everything seems to be going in the right direction when Taizan Himuro returns to the office and starts working on stopping the war in a diplomatic way. But the invansion of Hokuto has started already and Sento is unable to stop Ryuga without using the Hazard Trigger, a power up that even Katsuragi thought is dangerous.
I Have No Son!: After Taizan is cured and returns to the Ministry, he respectfully calls out Gentoku for attempting to invade Hokuto with an army. Then he disowns him and tells him to leave Touto much to his shock. A pissed off Gentoku steals the Pandora's Box in response.
Internal Reveal: Soichi explains to Sento the predicament with the Hokuto Crows and their upgraded Smash forms.
Stating the Simple Solution: When Sawa points out that Taizan never would've declared war on Hokuto, Misora's first suggestion is just use her new healing powers to heal Taizan so he can give his warmongering son the boot. And that's exactly what they do.
The Medic: Based off Misora's newfound healing powers, Misora ends up healing Ryuga's combat wounds but ends up tired. Then Sawa convinces Misora to sneak into the hospital to see if they can cure Taizan Himuro and wake him up from his coma. Despite a minor hiccup, it works and Taizan is able to regain his status as Prime Minister.
Tempting Fate: Sento asks Aoba if they really die after being beaten in battle. Aoba proclaims he is not going to die because he promised Kazumi. This doesn't work out very well for him in #21.
Try Not to Die: Grease decides to forgive and work with the Crows under this condition. An embrace ensues.
We Will Meet Again: Before Gentoku escapes after his battle with Sento, he promises that he'll return even stronger than before.
Nature vs. Nurture: Soichi describes Banjou as being a natural fighter that represents nature while Sento represents nurture through growing stronger with science. He wants the two of them to motivate each other to get stronger.
What the Hell, Hero?: Kazumi slaps Akaba, generally upset with the trio's choice to administer the Hazard Trigger to become Hazard Smash. Aoba replies that it doesn't matter what he thinks since he can't remember them.
