At the beginning of Shadows on the Stars, the wicked spirit Rhita Gawr corrupted this pure crystal of élano and thereby transformed into an anti-matter-like version of itself, called vengélano, which destroys whatever it touches.

Scree must confront his greatest mistake, which nearly cost him his life and the staff of Merlin, to help defeat Rhita Gawr's army.

He discovers, among other things, growth rings of the Tree that tell its history; places where giant termites dwell; and the Ayanowyn, whose once glorious society has become a dystopia.

Because, as a rule, humans think of trees as being wooden, the description of Avalon's trunk as being essentially made of stone and consisting of such topography as exists in our real world creates some ambiguity.

In or near Merlin's Knothole, Tamwyn meets Ethaun, a blacksmith and the sole survivor of his father Krystallus' expedition to the stars.

When the aid comes slowly, they leave via the portals that link the seven root-realms; mistakenly to the realm Malóch, where they learn that Elli's former tormentor Llynia is part of a eugenic, genocidal effort to impose human rule.

Escaping from Llyina's clutches with the help of a gnome whose life Elli had saved in the previous book, they continue with greater urgency.