What's Homestuck about?
It's a tale about a boy and his friends and a game they play together.

On his 13th birthday, John Egbert starts playing a mysterious videogame called Sburb. Unfortunately, this triggers the apocalypse. Fortunately, he and his friends can make things right—if they can beat the game. They’ll need a lot of teamwork, a little luck, and some inspired shenanigans along the way to make it through this mind-bending, genre-defying adventure.