The show is about to begin, so please switch on your mobile phone.

Not an instruction that typically greets you at the start of an Edinburgh Fringe production, but then City Of The Blind is not your typical sit-in-a-room, face-the-front sort of event.

Part of the Made In Scotland Showcase 2014, it comes from the imagination of writer-director David Leddy and Scottish theatre company Fire Exit, who previously led audiences around the backstage labyrinths of the Citizens Theatre in Glasgow and Hill Street Theatre in Edinburgh for gothic-horror promenade piece Sub Rosa. This time the stage is your smartphone or tablet and the show can be watched anywhere.

Leddy has a globally serious and sickeningly true tale to tell here, albeit wrapped up in the genre trappings of a political conspiracy thriller. Cassie Al-Khatib (Claire Knight) is an investigative auditor working at the United Nations headquarters in New York. While looking into how South American drugs money entered the US economy during the banking crisis, she stumbles on what seems to be another cover-up: an organised ring of gang rapists, all of them UN peacekeeping soldiers, has been operating in Democratic Republic of Congo. Incidences of male rape have been buried deep within the UN's files, and Cassie must turn whistleblower to bring these crimes to the surface.

The story unfolds in six "chapters" assembled from genre-appropriate content: CCTV footage, wiretap audio, email and text message exchanges, surveillance photos. It's an incredibly immersive means of drawing the audience into the story, as the voyeuristic nature of the material itself renders the viewer more complicit as the plot unfolds: Cassie is our heroine and we sympathise on a human level with the emotional problems she's undergoing with her sister and boyfriend but, listening in on headphones, we feel like we're detached and spying on her ourselves. It's an entertaining experience - red herrings and chapter cliffhangers keep us guessing - but Leddy pulls no punches with the documents gathered together at the end of each section. These authentic newspaper articles and UN reports prove that the essence of everything we've just seen is absolutely real.

This crashing together of investigative fact and theatrical fiction is presented in a more traditionally tangible format in City Of The Blind's companion piece Horizontal Collaboration, a live show that's part of the Traverse's daily programme. Here four UN staff lawyers at The Hague read pre-prepared texts at a tribunal. The case that emerges concerns Judith K, wife of an African warlord, who enters into a sexual relationship with a UN peacekeeping officer after her husband's assassination.

Leddy's decision to cast four different actors for every show, none of whom has seen the text before, underlines the in-the-moment nature of live theatre. Stripped back to one table, four laptops and eight desklamps (which are switched off, one by one, as the show slips into a moral abyss), it's possible to see flickers of human emotion on the faces of each actor/lawyer as, without rehearsal, they read horrific accounts of sexual violence for the first time. The roles are not gender-specific: I saw it with four women in the cast, but I'm sure a male actor as prosecutor challenging a rape victim, or a male actor delivering a rape victim's testimony, would add a different frisson to the proceedings at another performance.

City Of The Blind and Horizontal Collaboration are connected but separate, the former technologically complex, the latter dramatically pure. Each examines lust for power, first-world hypocrisy and rape as a weapon of war. The refrain "I have no idea what happens next" runs through them both, connecting the many levels on which these inventive productions operate: part thriller device, part admission of helplessness, part challenge to the audience to do something about the issues raised.

To access the production, visit http://cityoftheblind.davidleddy.com