There's this theater in the City that's been renovated and updated over the years. It was built at the turn of the century and it has been in operation for over a hundred years. Lots of things have changed with every project to "modernize" the theater. Except for one thing: A intercom phone that used to be used to contact the different areas of the theater during a performance. It's the only one left, surviving every architect's plans to pull the theater into the future.
It's an antique from the 1950s, an updated version of an older updated version, of the original system that was installed when the theater was constructed. It's no longer connected to anything, the wires are visibly cut, and the theater folks, actors, stagehands, the like, all get a chuckle at it, but would fight to the death to keep it in the theater. Not because of it's history... no...
It's because you can call people... people who are no longer among the living. Former employees of the theater, especially the Stage Manager, Fred Ferguson. Fred ran the theater from 1950 to 1975 when he passed away in his office, working on a problematic production of Hello Dolly. Everyone that you can call on the pushbutton list of areas of the theater all died there in various ways. Davis James used to run the curtains, until he was crushed by a sandbag that fell from the rigging. Ursula Sanchez was electrocuted using a hair dryer in the communal dressing room for the bit part actors. Nothing gruesome, but at least one from each department in the theater:
Stage Manager
Prop Shop
Green Room
Fly System
Dimmer Room
Trap Room
There used to be one to the Box Office, but since it's been renovated dozens of times, that line is... dead. The Fly System, the system of ropes, counterweights, and other mechanisms for "flying" things, curtains, and other things you can do with that system, is due to be updated to a automated system that doesn't require anyone in the wings to operate. If you talk to Davis, he's worried, and he's harder to contact. And he wants to tell folks about something, something in the theater that's scaring him. The others haven't seen it yet, but Davis... he's seen it up in the rigging and it's waiting...
So the set up is a viral tweet from a stagehand about what Davis was talking about. It gets flagged, and your team is sent to investigate this mystery. I'll leave it up to the GM to determine what this "Phantom of the Rigging" is and why it's a danger. Feel free to put a countdown on this, in the form of the contractors are arriving in short time to start with the renovation of the Fly System. When it's done, Davis is off to the big theater in the sky.