Olin, Hildr and Frode stood stalwart as the undead army approached. They had set their traps, prepared all they could but it was a long time till morning. They knew that the only way to keep the Illustrious City of Silasthorp from falling was for the three of them to hold the Bridge.
“Well Olin,” Hildr began as she grabbed her axe from her belt and turned toward the hardened warrior. “We may feast in the halls of Valhalla before this night is through”
“Odin owns us all,” Olin replied. The three then shouted the known refrain in unison as the undead army was upon them.
Whether it is the rickety rope bridge in The Temple of Doom, a strategic bridge to war effort like in Saving Private Ryan, or the last place you have to stop the Balrog a la Fellowship of the Ring, a Bridge encounter is always a classic Set Piece. One of the more exciting ways to use a bridge as a chokepoint, a place to hold from an overwhelming force. So let’s give that a go.
Evil must be stopped and this Bridge is the last place for your heroes to make their stand. Have they had time to prepare or are they desperate? There is hope however, they only have to hold out for so long. Wherever the scene is, be sure to describe the bridge itself in great detail make sure you include features for the players and the enemies to exploit narratively. How’s it lit? is the railing weak in areas? Are their pot holes? Is there cover? This is going to be longer encounter be prepared with a few ‘intrusions’ that could alter the landscape and shake things up. Don’t be afraid to choreograph them in your description maybe your players get the idea to trigger events first for their benefit.
Desperation can be the prevailing mood or Defiance. It all depends on the setup. It could be a solemn scene about honor and glory. Standing tall to protect the innocent. A lot of this depends on the type of game you are playing and the characters in it. Which is cool because your Bridge Fight scene in Achtung! Cthulhu is going to look and feel completely different than the epic defense upon the Bifröst.
Threats should be numerous but relatively disposable. Minion groups, mooks, one hit kill enemies that your players can kill easily and have a small chance of doing real damage to the players. Every few rounds pepper in more challenging foes. Then after that maybe a single even larger challenge. Your player’s fighting resources may be running low encourage them to get creative in how they handle an adversary, hopefully, they work together.
Standard Combat mechanics apply. I’m not big on games with tactical mini type combat I can see a scene like this being a real slog for that type of game, or a lot of fun it really depends on your table, but regardless make sure you have some environmental features. Falling off the Bridge could/should be a threat to the PCs and enemies alike don’t forget that.
Have a defined end. If they don’t make it to the Celestial Heart by dawn the undead army with turn to dust. Or maybe the party’s occult scholar needs to complete a complex ritual to banish the army. Reinforcements will arrive in a few hours. The airstrike is on its way. Something. Make sure the players are aware or the timeline, otherwise the saviors can feel like Deus Ex Machina or GM fudging and not something they earned.
Feel free to skip ahead in time. If help comes at first light you will have a lot of rounds to go through. After they complete a wave feel free to say “Three hours later we see Olin Hildr and Frode still on the bridge, how does Olin look as he dispatches his latest foe? Is there any noticeable wounds?”
Don’t just keep throwing in the mooks. Break up the combat. Allow a few seconds of respite as the threats build. After the PCs have dispatched the last wave of foes there is an ominous lull as the Death Knight makes his way to the front of the army.
The campaign ending epic defense is a great place for player death. Be sure to gauge your players see if they are cool with the idea of going out this way, and make sure the death is heroic. (no getting knocked off the bridge) however, if this fight is still early in the campaign a sudden untimely death could ramp things up.
If the players have a few major NPCs with them, at least one should die here. The defense should not be without cost.