The game starts as two sisters, Yuki and Ayame, are on a trip to visit their uncle's farm. However, they haven't met their uncle's family and are a bit anxious about it. Are they going to be accepted by their cousins ? Are they going to have fun in a farm ? But they'll soon find out that they had nothing to fear and that this trip will certainly be the most life-changing event of their lives.

Vitamin Plus is a hentai game. It means it's an adult game for people who likes Japanese drawn porn.
It's a game created with RPG Maker VX, a software made to develop RPGs.
However, Vitamin Plus is more like a visual novel/adventure game. There are lots of dialogues, but you'll also have some item searching or puzzle solving.
The more you'll evolve in the game, the more options will become available in terms of gameplay.
Of course, the main goal of the game is to find all the hentai scenes (some are hidden, some are not) before the end of the game.
It's important to note that the game contains strong fetishes that may not be everyone's taste. However, you'll find the list of those fetishes before the title screen, so if one of them bothers you, you can still close the game.