Twine is a tool for creating interactive fiction, or "Choose Your Own Adventure" stories/games
Getting Started - instructions on how to get started with Twine and add pictures or change fonts and colours
An starter story that uses variables that you can change into something more interesting. Click on this link: Library Adventure to read the story. Right-click on the page itself to save the html file so that you can upload it to Twine and edit it.
The instructions on how to go about changing the story into your own version