Twine

Opensource tool for telling interactive & nonlinear stories

Screenshots

Hunter's comment

Twine is an open-source tool for telling interactive stories. You can write your stories with this tool in HTML and share with your friends or followers. Because of Opensource, it is free to use and you don't need to pay anything. You don't need to write any code follow the User friendly interface and you are done.

You don't need to write any code to create a simple story with Twine, but you can extend your stories with variables, conditional logic, images, CSS, and JavaScript when you're ready.
Source

Link

http://twinery.org/