What would we do if we had one group of PCs (Aggressors) trying to do something that requires a linear, and another group of PCs (Defenders) trying to stop them? Assuming the Defenders can't stop the Aggressors during interactives, the conflict will have to be run as a linear. The options are below (note that while the Aggressors in most of these could be described as the evil ones, this is not necessarily the case - it's just easier to think of it that way round):
1) Run the event as a linear for the Aggressors, with the final encounter being the Defenders turning up at the last minute to stop them. This is probably the way to go if achieving the mission is much harder than stopping it, because the Aggressors will be fatigued from the linear while the Defenders will be fresh and well-prepared. This may well result in TPK for the Aggressors unless they massively outweigh the Defenders.
Advantages: Really easy to run - Basically a normal linear with PCs as the final encounter.
Disadvantages: Screws over the Aggressors because the final encounter is other PCs; the Defenders don't get to play a full linear.
Suitable example: The Aggressors go to Windy Peak, hack their way through the Air Elementals, and do an Earth Ritual on the ley nexus to banish all the elementals. The Defenders make a deal with the Elementals for safe passage to the ley nexus in exchange for stopping the ritual.
2) Run the event as a linear for the Defenders, with the final encounter being the Aggressors in the middle of their rite/ritual/whatever. This is probably the way to go if stopping the mission is much harder than completing it or the Aggressors have made a lot of progress in previous interactives/downtimes, because the Defenders will be fatigued from the linear while the Aggressors will be fresh and well-prepared. This may well result in TPK for the Defenders unless they massively outweigh the Aggressors.
Advantages: Really easy to run - Basically a normal linear with PCs as the final encounter.
Disadvantages: Screws over the Defenders because the final encounter is other PCs; the Aggressors don't get to play a full linear.
Suitable example: The Aggressors go to Windy Peak and make a deal with the elementals to level the entire City with a hurricane in exchange for the power in the Wessex Arms ley nexus as well. The Defenders have to fight their way through the Elementals to stop the ritual.
3) Run the events as two simultaneous linears, starting at opposite ends of the course and meeting in the middle. This just plain won't work unless we have the entire society available to monster AND about three sets of walkie-talkies.
Advantages: Everyone gets a full linear and a final encounter on approximately equal terms; speed matters; closest reflection of actual events.
Disadvantages: Logistical impossibility.
Suitable example: A messenger from the King of Wessex was robbed by goblin bandits. The message he was carrying holds a terrible secret which could endanger the stability of the country should it ever be made public! Unfortunately, due to a monumental cock-up, this news was announced to the entire bar, and now the Goblins have been tracked down, both the Army and a group of revolutionaries have set out to get to the goblin den first, approaching from different directions.
4) Run the events as two linears on consecutive weeks, the first one for the Aggressors and the second one for the Defenders, with the final encounter of the second linear being the Aggressors in the middle of their rite/ritual/whatever.
Advantages: Easy enough to run; both parties get a full linear out of it.
Disadvantages: We need to explain the week-long gap in the middle; it takes up two linear slots instead of one; if one of the Aggressor players can't make the second week it sucks; the Aggressor characters can't attend the interactive in the middle.
Suitable example: The Aggressors take over a small demon-infested plane by force and attempt to crash it into the elemental plane of Darkness. A week later, the Colleges of Magic notice the incoming kamikaze plane, and the PCs are sent to recapture the plane and stop the destruction.
5) Run the events as two back-to-back linears in one day, the first one for the Aggressors (with the players of the Defenders monstering) and the second one for the Defenders (with the players of the Aggressors monstering), with the final encounter of the second linear being the Aggressors in the middle of their rite/ritual/whatever, with whatever hitpoints/spirit/magic/effects they had at the end of the first linear.
Advantages: Both parties get a full linear and a final encounter out of it. Actually possible to run, although not easy by any means.
Disadvantages: Either the linears are very short or we need to put aside a whole day.
Suitable example: The Aggressors fight their way to the nastiest bit of the Dreaming and begin to summon a Nightmare that haunts the dreams of the Gods themselves. The Defenders are hot on their heels but still have to fight their way through the hostile terrain and vicious inhabitants of the Dreaming.
6) Screw the bulk of the linear and just run an enormous final battle between the Aggressors and Defenders in a big field.
Advantages: Easy as pie to run.
Disadvantages: No actual linear, just an apocalyptic final encounter.
Suitable example: The Aggressors have slaughtered an entire village and turned them into Undead! They must be stopped before they can create any more carnage!
Other things to consider:
--Koryne
8) Run the whole thing in the Persistant World style rather than the Linear style (e.g. The Sword Of Humact linear, the Creed's Hill PBB) starting player parties off in different locations but having the same things wandering around for them to encounter
Advantages: Persistant World is a fantastic way to run linears anyway, everyone gets a full linear
Disadvantages: Almost impossible to run in the Meadows, very difficult to run out any real combat encounters, could really do with lots of monsters, needs careful setting up and briefing to avoid NPCs Talk To Each Other Syndrome or Everyone Kills Each Other In The First Five Minutes And Goes Home
Suitable example: The Sword of Humact nonlinear, Creed's Hill PBB
9)Run separate linears, with some kind of scoring system: a linear for the aggressors one week, and a linear for the defenders the week after, with the outcome depending on who "scores" more. "Score" could be a matter of e.g. who completes their linear faster, do group A manage to save more peasants than group b) kill, who finds more of the shinies hidden along/around their linear, etc.
Advantages: much less likely to result in one side or the other being TPKed; lends itself well to partial outcomes rather than winner takes all.
Disadvantages: requires a week's break in the middle; less opportunity for direct opposition unless the refs set up something clever; less interactive.
--Jacob