That sounds like a dreamscape with a pulse. Start by giving the city a heartbeat—midnight is when the clock resets and so does the map. Maybe the main character is a cartographer who notices that the same alley becomes a river one night and a ballroom the next. Layer the plot by making the protagonist’s goal tied to a missing person whose last known location shifts each hour. As the city rewrites itself, secrets from its past seep into the present: a hidden library of forgotten memories, a market that sells regrets, a bridge that appears only for those who truly want to cross. Each shift reveals a piece of the city’s lore, like a puzzle that the protagonist must solve before the next midnight to save the person—and perhaps the city itself. Sprinkle in a twist: the city is rewriting to erase its darkest history, but every change also erases something of the people living there. That tension can keep the stakes high while letting you explore how memory and place shape identity.