The River in the Sky

The city has fallen. Soldiers march through the streets searching for anyone important. The royal family and council have been evacuated. There should be no one important left. Except Cassaline didn't leave when she was meant to. And now has information that could save or doom her city. The only way out is based on a legend from a millennia ago when Heroes walked the paths of the spirit realm. Those legendary heroes had knowledge and spirit guides while Casa has neither.
She's willing to die to save her home but is death the same in the spirit realm.