Motto! Haramase! Honoo no Oppai Isekai Oppai Spy Gakuen!

A boob-obsessed ninja descendant gets sucked through his dead father's scroll along with his stacked stepmother and stepsister, landing at a Spy Academy where every student, teacher, and even the principal is a spy with an enormous chest. Nobody in this school covers up quietly, and neither does the plot.

After getting cornered naked in the dorm bath by a mob of busty students, the protagonist is "rescued" by the principal, who immediately hands him a mission: hunt down an enemy spy hiding somewhere in the academy. His inherited "Perverted Mission Skill" turns out to be the only tool that works, and the principal is thrilled about it. Now he's expected to investigate the school's most influential spies and their equally well-endowed mothers, all of whom are trying to pry loose the knowledge he brought from his own world, and all of whom set honey traps of their own the moment he gets close.

The player reads through this kinetic-novel espionage romp as the protagonist bounces from one busty target to the next, using his lewd skill to flush out secrets and enemy agents while the school's honor students, teachers, and matriarchs come at him in turn. There's no branching to steer, just a fixed string of missions escalating from bathhouse ambush to full academy-wide entanglement, voiced and animated for the parts that matter most.