It took him four hours to call. When your ex-girlfriend's hometown mysteriously blows off the map, you get worried. It only took a few minutes to reach her cell. A few hours to contact his superiors. And a week to get the papers.
It was the biggest ever, Riley, and I can't handle the aftermath alone. We're talking unintended consequences in a major way. And I could really use your skills and connections.
A mysterious explosion, possibly related to terrorist activity centered around subversive elements in a Southern California town. A highly-classified secret department affiliated with Homeland Security and had access to all manner of specialized training for both body and mind.
It was been her choice to awaken all that power, and she'd remembered how hard handling it was. She'd liked it, but had never really asked for it, and didn't really want it all that much either. But she believed in responsibilities. Something would need to be done for all these girls. And she knew people with the power, resources, and honest desire to help. Who both wanted to show her how much they respected everything she stood for. And still felt guilty about running out of her life, and leaving her to die alone. Life was looking up.
"I'd like to think we have compatible mission statements, although our methods and jurisdictions are pretty clearly different. to be honest, I don't know how involved we can get. I can try to help, but in the end, this is really your world and I'll have to count on you to keep this from blowing up."
Buffy's experience blackmailing the Doublemeat Palace, and Willow's files on the supposedly-never-existed Initiative proved extremely handy. After a few tense phone calls, she finally got cooperation from Riley and whomever he worked for to forge a tentative alliance. The girls would need real training and fast, they'd want some idea of where and where not to go, and some assurance that they could keep the new slayers safe from uber-shadowy, cigarette smoking men. Or women.
Riley bristled at working with Angel, but as Buffy pointed out, he was older than the US Government and likely would last just as long, so they might as well get comfortable working together.
I want you both to talk with each other. It's for the good of the world, and for the good of all these girls. I believe that you both have a lot to contribute, especially if you can make peace. Prove me right.