As Tallis' shamanistic powers grow, she undertakes a quest in Ryhope wood to find her lost brother and undergoes a metamorphosis of her own.
During her formative years, Tallis encounters the British composer Ralph Vaughan Williams (not a mythago, but real flesh and blood).
When properly used (especially later in the book), these masks allow Tallis to see things that cannot be seen without them, and they can also be used to create 'Hollowings' — pathways in space and time which allow her to step into far-off places within the wood which would otherwise take days, weeks, or even months to travel to on foot.
In terms of content, Lavondyss has a 'darker tone' than Mythago Wood due to its relentless focus "on the earth, stone, blood, dung, and death that are the necessary roots of the story.
"[7] John Clute describes Ryhope wood in Lavondyss as a "metamorphic terrain of daunting rigor, an excremental sign-saturated inscape charged with twisting energy.
"[1] Mythago Wood and Lavondyss have been described as being significant because they are pure fantasy works that take place in an innovative, yet startlingly ordinary realm.
[8] Mythago Wood and Lavondyss have been described by Michael D. C. Drout as being two of Holdstock’s best works which, as fantasies, have an internally consistent framework of principles.