Fallout 3 crossover:
Huge imbalance caused by activation of all potentials causes world-wide demon invasion. Slayers and conventional armies rise to fight, but are steadily losing ground. In meantime governments proceed with contingency plan - create multiple underground vaults when part of population can stay hidden from demons. Finally when resistance collapses, in last desperation strike all nukes are launched.
Core Scoobies survive, but go separate ways: first to leave is Xander - he manages to secure place in Vault 101, right before it gets closed. His role is to protect Vault pop...

Scoobies accidentally bump into SG1, but this time it does not go well. One side immediately jumps to "military = next Initiative" conclusion, the other mistakes supernatural powers for alien technology. Later something happens that makes any chance of reconciliation impossible - like a soldier panicking and killing Xander. Each side is completely convinced that the other one is 'bad guys' and have to taken out for humanity safety. Because Scoobies and SG are wasting more and more resources on war against each other, they turn backs on actual threats - demons and aliens.

Main points:...

In about every crossover NID appears as a group of villains just waiting to grab a slayer or a witch for some torture and dissection. What I would like to see is Buffy/Stargate crossover where NID works as it was intended to - protecting their country and planet whatever it takes and willing to make tough decision if necessary. Specific plot points I would like to see:
- Buffy and preferably Willow joins legitimate branch of NID (time line for SG1 is after agent Barrett becomes head of the organization)
- Buffy & co saves SG1 after their dumb luck finally lets them down
- conf...