No, this is not a Walking Dead pun.
A “walking news story” is one that develops over time, though often a short amount of time. For instance - Your party will be in their home town for three weeks between missions, and they like to keep in touch with contacts, suppliers and bartenders. So the first story is something like: Hey, Did you hear? Bob Smith found a chest of gold coins just sitting on the side of the road. Keeps talking about money from heaven. Couldn’t happen to a worse guy. That’s all anyone knows on day 1.
Day 2 - Now people are hearing that Bob Smith actually claims the money fell out of the sky. Rumors start flying that he must have robbed someone. Bob can be found in the casinos spending his money like the idiot he is, maybe even buying the players a drink.
Day 3 - The merchants in town don’t have all the details, but they are hearing that one of their own lost a wagon that had a chest of gold coins on it, and boy are they mad. Doesn’t take a genius to put two and two together and blame Bob.
Day 5 - Bob has been murdered.
OK - So you might ask - who cares? That all depends on what you want the outcome to be. Here’s the real story: A tornado hit the wagon with the chest. Everything (chest included) got thrown around over a mile of terrain. Bob was hiding in a gully, waiting for the storm to pass (he did not fully realize it was a tornado, just a bad storm). He prayed to the goddess of luck to save him, and then the chest fell out of the sky. He of course gambled it away. But the true owners of the gold wanted it back, so they sent their guys to go kill Bob, recover the money, and make it look like some regular thieves took it from Bob because he was too open about his luck. They’re still pissed because they got less than half of it back.
Again, does anyone care? Well, this could just be a good story, something for the bar flies to talk about over drinks. But what if they want to get involved? What if your players decide to rob Bob? Well, now the merchant is looking for them, and this guy has the long fingers of the vastly wealthy. What if it wasn’t chance, and the goddess of luck intended to reward Bob for his prayer? Is she going to send some divine retribution at the merchant for thwarting her plans or was she giving Bob the money knowing he would gamble it away at one of her casino temples? What if the merchant hires the players to get the gold back? What if the city hires the players to collect the bounty on the murderers? What if the players go out and realize that there was a tornado? I assume the merchant knows Bob didn’t rob them, just profited from a freak storm, but he doesn’t really care. What if the tornado wasn’t a tornado but a battle between a major air spirit and a major water spirit? Could this be a prelude to something bigger and more important? Could there be an injured water spirit out there who might reward those who help him (maybe in capturing the tornado spirit)? But again, maybe they just talk about it in the bar, and nothing changes. Then again, this is high fantasy and the most mundane things like what seems to be a robbery might just be a war amongst the elements.