In caged demons... the way the one tried to use Spike they can't be out for good; without Buffy interfering it would have been released.
Mmm the others arrived; good that they can track Buffy and Spike; almost important to find them without it.
Ah gotcha; McGee is the watcher that stole the crystal. Suspected something like that because he that he had hid it. And he's not up to good things (but we knew that already).