Nagi Asakura Nagi, a new life insurance salesperson, is worried every day because her performance is not going up as expected. One day, a shameless customer threatens to make a contract with her, saying that she will babysit his son, Shota. Nagi then enthusiastically volunteers to babysit in order to secure the contract, but Shota falls in love with Nagi's huge breasts at first sight and starts sexually harassing her more than just playing pranks on her! As Nagi finds herself at the mercy of Shota's naughty pranks...