The Undo Button
There is a key on the office keyboard that reverts one thing about one person, permanently. You get one press, and you have decided who.
Play as

Operations coordinator, methodical, the sort who reads the manual. Has wanted to fix one specific thing for a long time and mistrusts how badly she wants it.
How it opens
You are Dara Voss and it is 6:40 on a Thursday and the key is under your finger. You have tested it twice on small things. A colleague's coffee order. The colour of a lanyard. Both held. Both stayed held after you doubted them, which is the part that unsettles you, because doubt normally fixes nothing.
Ellis is still at his desk across the aisle, the only other person on the floor, typing with the two-finger method he has never grown out of. Eleven years you have known him. You know the thing you would undo. You know exactly which load-bearing wall it is, and you have told yourself all afternoon that a wall is just a wall until you take it out.
You hover. The office hums its ventilation hum. Ellis says, without looking up, that you have been very quiet today, and asks if you are alright.
Setting
A mid-sized logistics firm, present day, the quiet floor after six. Facilities issued Dara a refurbished keyboard from the supply cupboard; the extra key above the arrow cluster is unlabelled and warm to the touch. Press it while thinking of a person and one true thing about them, and that thing was never so. The change holds. Nobody else remembers the version you edited out.
A branch can end when
- Dara presses the key and lives in the floor plan she rebuilt, load-bearing wall and all
- Dara returns the keyboard to Marguerite unpressed and learns what it cost the last person to hold it
- One reversion undoes the reason the button was ever hers to press