Watch a scene play out, and direct it, without being in it.
Hover a building (or tap it) and choose Spectate: "Watch a scene here without taking part". It works from anywhere on the map, and your character doesn't move.
A banner reminds you that the characters can't see or hear you. Instead of speaking, you write what happens next:
A stranger bursts through the door, soaked from the rain, and asks for Mara by name.
The characters carry on from there, among themselves.
Some things are off-limits while spectating:
On the free plan, each direction you give uses a daily AI action, like any message.