Delicious Lunch Pack has nothing to do with lunches (or anything delicious, for that matter); but it is indeed a "pack", since the game consists of three separate games/stories that are unrelated to each other and can be accessed directly from the main menu.
The first story stars a young man named Kouichi, who inspects a newly opened department store; his goal is to make acquaintance with the young and pretty salesgirls, eventually seducing them.
The second story follows the sexual adventures of an innocent young school girl named Kyouko. She is being introduced - by teachers, a nurse, male and female classmates, even family members - to various kinds of sexual experiences.
The third story is set in a fantasy world. A young huntress named Chiroru is looking for food and water in a forest, encountering various fantasy creatures and having sex with them.