tl;dr: BNF are non-linear games where players shape the story. WhatIF is a tool that helps developers design, analyze, and refine branching plots, overcoming challenges like writer's block.
Branched Narrative Fiction (BNF) are non-linear, text based narrative games, where the player of the game is an active participant shaping the story. Unlike linear narratives, BNF allows players to influence the direction, outcomes, and progression of the plot. A narrative fiction developer designs these branching storylines, creating a dynamic interaction between the player and the narrative which requires significant time and skill. In this work we build and investigate the use of a visual analytics tool to help narrative fiction developers generate and plan these parallel worlds within a BNF. We present WhatIF, a visual analytics tool that aids BNF developers to create BNF graphs, edit the graphs, obtain recommendations, visualize differences between storylines and finally verify their BNF on custom metrics. Through a formative study (3 participants) and a user study (11 participants), we observe that WhatIF helps users plan and prototype their BNF, provides avenues to support iterative refinement of narrative and also aids in removing writer's block. Furthermore, we explore how contemporary generative AI (GenAI) tools can empower game developers to build richer and more immersive narratives.