A recurring theme in The Tale of the Five involves characters overcoming or otherwise acknowledging the flaws in their personality that prevents them from becoming more powerful, and defeating The Shadow (a fallen power created by the Goddess accidentally letting entropy into the universe she created).
The primary character of The Door into Shadow is Segnbora, a young swordswoman who has the potential to be one of the most powerful Rodmistresses in the history of the Middle Kingdoms. Her natural ability to use the Blue Flame is so powerful that apparently, she has broken every rod she has tried to focus with. Because of this failure, she has tried to excel at many other professions, and while she keeps acquiring new skills and honors, she is eternally restless and unhappy because the only ability her parents seem to care about is her potential to wield the Blue Flame.
Her restlessness caused her to be in the right place and right time to help Freelorn. Segnbora joined his band of followers after rescuing him from an assassination attempt in Steldin. She also briefly had a relationship with Freelorn during the previous book, which will become important in the third book, The Door into Sunset.
The Door into Shadow opens up with a newly focused Herewiss, who need to learn how to do everything fast, before the Shadow tries to squish him. The best way to do this is to visit a mystical hotspot called the Morrowfane, where in very ancient times, a large number of Blue Flame wielders died sinking their power into a sacred lake so that the methods for using the power would not be lost during the cataclysm that nearly destroyed the world.
Lorn and his band, plus Herewiss and Sunspark (who is learning about things like “humor,” though it does not always appreciate when you try explaining something to it) head to the Morrowfane. On the way there, Fyrrd, mutated animals that had been created by the Shadow during the cataclysm attack them. They fight off the Fyrrd and are able to reach the Morrowfane intact. While Herewiss is communing with the sacred lake, Segnbora wanders off and runs into a dying Dragon named Hasai.
The Dragon seems to know her, which is a little disturbing, but Segnbora agrees to stay when Hasai asks her to, because he says he doesn’t want to die alone. Of course, it turns out there was some fine print Segnbora hadn’t read. When Dragons die, they get a second “half life”–go “mdaha”–existing in spirit inside the mind of their nearest descendant–referred to as a “sdaha.” Hasai doesn’t have any children, and is in danger of going “rdaha”–dying completely. When she agrees to stay with him, she very suddenly becomes landlord to Hasai and all of his ancestors. Segnbora spends the next few days stumbling around in the inside of her skull while her knew roommates make themselves at home and dig through her memories–which makes her very angry, since there are some things that she left buried on purpose. Eventually, she is able to come to some kind of agreement with Hasai and his relatives, and is able to wake up.
The next stage of this story is to put Freelorn on the throne before Very Bad Things Happen. The “royal magics” that keep the Shadow at bay and the land producing crops have been left unperformed for way too long. To make things even more interesting, the Reavers (no relation to the scary neo-barbarian/not!zombies from Firefly) are coming through the mountain passes to invade again. Eftgan the queen of Darthen makes contact with Freelorn and his merry band to let it be known that she is more than willing to help Freelorn get back on the throne. She hadn’t quite been willing to interfere with Arlen’s business, but the usurper Cillmod has been raiding Darthen’s granaries (due to not being able to buy it since someone Freelorn-shaped decided it would be a spiffy idea to steal money from the treasury.) Oops. Eftgan however is willing forgive Freelorn for his stupid, because Cillmod may be under the influence of the Shadow, or at least, might have connections to someone who is.
Herewiss decides to fix the entire Reaver problem by dumping part of a mountain into the major “avenue” the Reavers use to invade. Since Hasai is a dragon and by nature very aware of geology, he volunteers to help Herewiss find the best way to dump rocks into the pass without causing a catastrophic chain reaction that ends up creating an earthquake that destroys the town that guards the pass. Important task number two involves Glasscastle, a supernatural phenomenon that periodically appears and disappears at certain times of the year. Glasscastle is supposed to be where suicides go when they die, and there are things living inside the ghostly castle that if summoned, would be extremely unpleasant for anyone who had to deal with them. Herewiss takes both jobs, because he is in “breakthrough” a short period of time after focusing where a Blue Flame wielder has an unusually strong burst of power.
While Herewiss is going about the necessary tasks to stop the Reavers and eventually, Cillmod, Segnbora is repeatedly challenged on various fronts. She is challenged by Hasai and the his ancestors, because while she accepts that they’re a continuing presence, and will use their knowledge, she won’t share her experiences with them. She is also challenged by various aspects of the Shadow, which attacks her through the darker sides of her personality–the reason why she has experiences she can’t and won’t share is because some of them were so traumatic she is afraid of being rejected because of them. Hasai also has to deal with his own fears–he had always known that eventually he’d go mdaha to a human, and because of this, had always kept himself apart, refusing to associate with anyone because of his fear. When they are both able to confront their fears and inner darkness, Segnbora is able to focus her Flame, and save the day.
You can get e-book versions of The Tale of the Five here