We’ve all done it, as DMs. The players come into town with a sense that things aren’t quite what they seem. There’s some simmering evil lurking just under the skin, and it’s up to the players to stop them before it achieves its goal. The Dragon Queen is rising, and if the players don’t stop her cultists, the world is doomed. The Giants are marching across the mountains with the intent of committing to a siege against the capitol of the human lands. All situations the players are asked to stop something before bad happens, but real life isn’t like that and that’s what I’m hoping each DM thinks about before they write their adventure: at what point in the villains story do the players enter?
The dragon queen rising is an interesting one, because it’s a quest that Wizards of the Coast wrote themselves. A way to punch it up, from a DM perspective, would have been simply to have the cults already won. The adventure would go from “Let’s stop them from getting treasure to the well of wyrms” to “how did they raise a dragon queen from her prison?”. The players would have to seek out those knowledgeable in dragon lore, ask them how going about raising Tiamat works and then finding a way to lock her back up (or defeat her entirely).
Likewise, the players could instead arrive so early, evil hasn’t happened yet. Looking at the Giants, maybe the town wants to establish a diplomatic line of communication with the Giants. The players are assigned to escort the ambassador to the Giants kingdom. They don’t know (although it’s a good idea to foreshadow) that the ambassador has been replaced with a Doppleganger who is being paid by an elven prince to put the giants to war against the humans and by the time they hear about it, the human capitol will have been crushed to rubble and the refugees moved to a neighboring city!
The simmering evil festers in the undercity, but each time players take out one of the leaders trying to bring that evil to bear, two more appear. They obviously have a leader behind them, and as the players try to determine who that leader is. Of course, by the time they figure it out, the time has gone too long and the villain has already begun their invasion. There are casualties, so it’s not a matter of prevention but of repair: how do the players stop things from getting worse and then reverse or patch the damage already done?
Hopefully the idea of asking when the players enter the timeline from the perspective of the villain is something you’ll ask when approaching your next game. Then, the players won’t be preventing a Giant Siege, but experiencing the aftermath.