I know Ciera has received some warning from Morrigan, and that's why she went to stark for info. Morrigan told her there was powerful stones, the Tuatha'De'Dannan have other names for them don't try to pronounce them with human tongues... and that it was a risk of Morgan le Fay got a hold of them. (Morrigan as a Goddess of Death and Battle can see future battles, but as we know that seeing the future is only one 'potential'. ) But yeah I imagine most everything will happen when everyone is on Earth. xD