A free program for Android, by Ayist Games.

Novels: Choose your story is a free online role-playing game where you can write your own role-playing adventure story. 

Novels is based on a new genre of role-playing games: interactive stories. This means that the game is no longer static, but instead, you get to control the actions of your character. The stories you create in this game will change over time as you play and decide what your character should do in this situation. You will decide what will happen to your characters, how they will behave, and how the story will end.