Versu is a new interactive storytelling platform Richard Evans and I have been working on at Linden Lab. Some of you may have seen lead-up presentations about it at GDC (possibly long enough ago that it was still called Cotillion).

Today, the first four Versu stories are available for iPad. Clients for Kindle and Google Play will follow, as well as stories in other genres and by other authors, and both character- and episode-authoring tools will be made available to the general public in the future.

Versu focuses on character interaction as its primary form of play. The Versu platform can do rooms, objects, movement, and the “medium-sized dry goods” interaction of a typical interactive fiction engine, but it’s primarily designed for interactive stories about people: how they act, how they react to you, how they talk to you and talk about you, the relationships you form with them. The social landscape in which you act is constantly changing.

Versu uses an AI engine designed by Richard Evans, the lead AI designer for Sims 3, which allows each character in a story (and in some cases a drama manager AI) to act autonomously or be played by a human player.

Because there’s a strong social model at work in Versu, it’s possible to form relationships with characters that the story author did not explicitly create. In play, you can decide you want to pursue a romance or make an enemy, and that outcome can occur even if the author did not write an arc specific to those two characters.

Versu has a choice-based interface, but it’s very unlike standard CYOA. At any moment in the story, you can choose to act, or wait for others to act. If you choose to take action yourself, you’re offered a set of options drawn from the world model at that moment, from taking a bold stand to giving someone a significant sideways glance. Just about everything you can do affects your character’s opinion of the other characters, and theirs of you, altering the playing field for what’s to come. Inaction can be a powerful choice.

Versu offers moments of narrative emergence. Late in testing, one of my characters was talking to another in confidence when a third party wandered in. Because the speaker didn’t feel comfortable around that third person, he fell silent and didn’t continue the conversation — there was an awkward pause and dialogue moved on to other things. I’d never written the “awkward pause when X walks in on a private conversation” outcome — just an engine that knew when the characters would be willing to discuss those topics, and also that it was awkward for someone to stop talking about a conversation topic when others were expecting them to go on.

This can happen elsewhere too, in large and small ways. The degree to which emergent character behavior affects large story outcomes depends on how flexibly the author has written the overarching plot. “The Unwelcome Proposal” is an example of Versu being used very conservatively, capturing as much as possible of the story text from a scene in Pride and Prejudice, and allowing for few deviations from that story. “House on the Cliff” and “A Family Supper” have a much broader spectrum of possible results, depending on character choices and relationships. Even more sandbox-like experiences are in the pipeline.

Versu allows for characters who act distinctly. A social model is only interesting for building fiction if it doesn’t make everyone act like identical automata. In Versu, different characters are built with different abilities and parameters — not a handful or a few dozen character traits, but a potentially infinite range of quirks and habits. It is possible to craft social behaviors that are unique to just one character — giving one guy the ability to get under people’s skin more than anyone else, say — or to make a character who hates being in a crowded room.

In addition, because characters are defined as separate entities in this way, they could be transferred from one story context to another, and even cast in stories that weren’t specifically written for them.

The stories we’re releasing today are just a taste of what is possible with this engine. I’ll post more of my usual analysis content over coming weeks — what it’s like to write for Versu, the difference between authoring characters and authoring stories, details of the conversation modeling system, and more about what we’re expecting to see in the future.