Worlds Within Worlds describes how to run a campaign set inside a massively multiplayer online role-playing game. The book uses the 3rd edition d20 system. While the book does describe a fictional computer game Lost Realms of Conflict, it includes suggestions for creating new settings or adapting an existing computer game.

After a series of mistakes, Lost Realms of Conflict shutdown. Una Corporation purchased the bankrupt Earthquakes Games. Many speculated about the reason but with no news interest faded.

The release of the binocular vision monitor heralds the return of the Lost Realms of Conflict. The immersiveness of the virtual reality display is unprecedented. Lost Realms of Conflict quickly tops the MMORPG charts but something is not right. Players begin to disappear. Can you discover the secret before it is too late?