Simply put: an online writing game. Use your words to defeat monsters: The monsters drop rewards. Some of them are items you can equip to make your hero stronger. Visit markets, craft recipes, complete quests, advance from one area to another, defeat bosses, save a world infected by a mysterious purple dust.
The game side is just one part of it. You can also write and organize your files into projects And publish these projects so that the community and friends from around the world can read and comment on what you wrote.