NKCell - Natural killer cell - is a cell that can react against and destroy another cell without prior sensitization to it.
They are part of our first line of defense against cancer cells and virus-infected cells.
An NK cell attaches to a target cell, releases chemicals that breach its cell wall, and causes it to lyse (break up).

You are one of a genetically modified NKCell that can destroy viruses and bacteria.
In the game, you will be standing in a blood vein and slash incoming diseases/infected cells to keep the infection rate low, and help the host to survive.

The game is simple. If you see an infection, slash it!
Currently, there are 36 levels with 15 different types of diseases.
There are only a couple of musics in the game, but you can always disable the music and play anything you want.