"Listen up! From now on, I'm going to transform you from a helpless and disgraceful duke's daughter into a ruthless killing machine, ready to mercilessly take down our enemies!"
It all started on that summer day.
Alicia, the daughter of a duke, had her engagement suddenly broken by the second prince, leaving her in a dire situation that could lead to her family's downfall.
During these tough times, Alicia's servant, Abel, suddenly awakens with the memories of being a U.S. Marine Corps member. To change the impending future of destruction, Abel takes Alicia and executes a strategic retreat from their school. He's determined to transform Alicia, who's feeling down, into a full-fledged Marine!
"Put your hair in a bun, and add 'sir' at the beginning and end of your sentences!"
"What do you mean, sir!?"
After going through basic training, Alicia, who still looks like a noble lady, has become a Marine at heart. But now, her transformation leads her down an unexpected path.
In her journey, she encounters something she must protect and faces unforeseen challenges, all in pursuit of seizing her own future. What lies ahead for Alicia and the U.S. Marine Corps summoned to this different world?
To the otherworld, this is the United States Marine Corps.