When the messenger owls return to the Winter Woods with snowflakes from Pixie Hollow, Lord Milori finds a book on Wingology with the imported snowflakes. He orders Sled to take it to Dewey, the keeper of fairy knowledge. Later on, Lord Milori begins to worry (correctly) that a warm fairy was responsible for bringing the book to the Winter Woods, as the laws state that warm fairies and frost fairies are not allowed to cross over to the other seasons. Milori visits Dewey to discuss the matter. He reminds the Keeper of the border law and its importance and commands him to send all warm-season fairies who come into the Winter Woods back.
The next day, Lord Milori's pet snowy owl spots Periwinkle crossing the border, and rushes off to inform his master. When Milori reaches the border, Periwinkle is weak, and her wings have shriveled from the heat in the warm climate. Milori informs her that her wings will recover within a few minutes of returning home. At that point, Lord Milori commands Tink and Peri to stay away from each other for their own good. The two fairies reluctantly agree and part ways. Lord Milori then attempts to destroy the snowmaking machine that made it possible for Periwinkle to cross the border for a short period of time.
Afterward, Lord Milori finds Periwinkle in the library, and tells her why the border law was created: When Pixie Hollow was young, A warm-season fairy and a Winter Woods fairy met and fell in love. For weeks, they met at the border every sunset, and eventually, one disregarded the danger and decided to try to cross. Unfortunately, the fairy broke a wing, an injury that is impossible to heal. To prevent this tragedy from happening again, Queen Clarion reluctantly created the law.
Meanwhile, the ice-making machine gets stuck in the river and goes berserk, throwing off the balance of the seasons. Lord Milori and an army of frost talent fairies journey to the slowly freezing Pixie Hollow, where they begin to frost the Pixie Dust Tree, which will protect it from the harsh winter weather. After the tree is frosted over, Lord Milori sees Queen Clarion shivering, and offers her his cape for warmth.
Realizing what winter fairies' frost can do, the border law is abolished; warm fairies are allowed to cross the border, following that they have their wings frosted to preserve them. In the end, Lord Milori is seen alongside Queen Clarion, now his lover again, happily watching the other fairies celebrate the long-awaited unity.
Lord Milori makes a cameo appearance in The Pirate Fairy He is one of Zarina's victims when she releases poppy pollen that makes every fairy in the coliseum fall asleep.
- Just as Queen Clarion is the tallest living fairy in Pixie Hollow, Lord Milori is the tallest living fairy in the Winter Woods.