Lyric discussion by Aixsponsa 

This is the Forest Queen's song after Margaret has been kidnapped by the Rake. She doesn't want her adopted son to leave the forest or obsess over his lover, so she uses her powers to help the Rake and his victim to the other side of an uncrossable river (Annan Water) to get Margaret out of the way. Beautiful vocals, and explains the hero's origin and shapeshifting.

Also, I'm fairly sure it's "cradle of clay" and "I will fly YOU [the Rake] to the far side."

An error occured.