Eric, a former SSS-rank knight, retired because of severe psychological trauma. He followed the dying wish of a fallen comrade and came to the city to look after his "troublesome" daughter. His comrade's description before he died was baffling: "That girl is a little unusual, but she's a good person at heart. I'm counting on you."
Right up until he opened the front door, Eric thought his biggest challenge would be looking after a rebellious teenage girl. But reality hit him hard:
"You said she was 'a little unusual.' Did you mean she's an 'otherworldly dragon girl' who's impervious to blades and bullets and can take down an S-rank monster with one punch?"
And so began the warm yet explosive cohabitation of a former strongest knight seeking an ordinary, peaceful life and an adorable, socially awkward dragon girl with ridiculously high combat strength, living together like a loving father and daughter.