A teacher with a katana shows up to fix a broken school, but the real joke is that the delinquent students are right, he's the actual threat. The action breaks into pure absurdist comedy the moment a girl's magical underwear becomes her secret weapon, and somehow it works because the show commits completely to the bit. This is 1988 anime refusing to pretend it has any ambitions beyond making you laugh at how hard it commits to being ridiculous.
Ganpachi arrives at a crumbling high school with a mission: whip the rowdy delinquents into shape and prepare them for life beyond these walls. The students, however, have built something they actually care about, a tight-knit gang structure that keeps them grounded. When Hinako, their fierce leader, discovers this mysterious instructor plans to dismantle everything they've constructed, she decides to fight back with everything she has, including a bizarre secret weapon hidden in her underwear drawer. What unfolds is a collision of wills played for laughs and genuine action. Ganpachi proves harder to stop than anyone expected, but not just because he's skilled. There's something different about him, something engineered and wrong in ways that slowly become clear. The comedy stems from watching delinquents face off against an immortal teacher while the tone shifts between absurd humor and legitimate weirdness as the truth about Ganpachi's origins emerges. This 1988 OVA thrives on chaotic energy and doesn't take itself seriously for a second, perfect for anyone who enjoys action wrapped in ridiculous humor and willing to embrace the genuinely strange.