I'd like to see some sort of starting event or story to kick off the captains in their quest to save mankind, even if it's just a suggestion to have such an event.

I was thinking about this very same thing [...]. My thought is that you describe the circumstances that get the captain going [like a Kicker from Sorcerer], and you provide a tiny hint about the Scourge, like a color or sound or smell or something that the GM is obliged to use.

[1]