A high school student's mother passes away leaving her alone with her grief. The girl, Marimo, discovers the name of a father she never knew. Marimo sets off to meet him, but is completely shocked when she finds someone very different from the father she envisioned. Her father, Shinpei, a 38-year-old would-be private detective, is shocked too, and doesn't believe her until he sees the paperwork. With Marimo muttering "The worst father in the world"and Shinpei lamenting the loss of his freedom, these two are about to learn how difficult and rewarding a father/daughter relationship can be.