Lovers of the Red Sky^[4] (Korean: 홍천기; Hanja: 紅天機; RR: Hong Cheon-gi) is a 2021 South Korean television series starring Kim Yoo-jung, Ahn Hyo-seop, Gong Myung, and Kwak Si-yang.^[5][6] It is directed by Jang Tae-yoo and written by Ha Eun. The series adapted from the novel of the same name written by Jung Eun-gwol^[7] is a fantasy romance historical drama about the only female painter in fictional era Dan dynasty, who was briefly recorded in the historical records.^[8]

It premiered on SBS TV on August 30, 2021, and aired every Monday and Tuesday at 22:00 (KST) for 16 episodes.^[9]

Set during the Dan dynasty era when ghosts, demons and gods are involved in human life, the story recounts the fateful relationship of a female painter (Kim Yoo-jung) and a blind astrologer (Ahn Hyo-seop). It begins at the sealing ceremony conducted at the 3rd year of King Seongjo's rule where they try to extract Ma Wang (Demon King: god of Death), who is residing in former King Yeongjong's body, and seal it inside a portrait of the King painted by a divine painter. Though they manage to seal the Demon King successfully with the help of Samshin (goddesses of Life), the Demon King places a curse on the country that it will suffer from droughts and famine for years to come. He also curses the offspring of Ha Seong-jin (the officer who conducted the sealing ceremony) and Hong Eun-ho (the painter of the King's portrait). Both Ha Seong-jin's son, Ha Ram, and Hong Eun-ho's daughter, Hong Cheon-gi, are born on that very day. Cheon-gi is born blind due to the curse of Demon King.

Nine years later, the country has been suffering from severe drought and the royal shaman is preparing for the Dragon Rain Making Ritual. Ha Ram, as a child born with the energy of water, is noticed by her and she chooses him as the helper of rain making ritual. As they come to the capital to attend the ritual, Ha Ram meets blind Hong Cheon-gi who lives with her father, who had lost his sanity after the sealing ceremony. The two children make memories with each other and promise to meet again after the rain ritual. But, unexpected things happen at the ritual. The King's portrait in which the Demon King is sealed gets burned and the Demon King enters Ha Ram's body. Ha Ram who was sacrificed in order to make rain, comes back to life with his sight lost while Cheon-gi miraculously gains her sight since Samshin takes the Demon King's eyes and leaves them with Cheon-gi.

Now, 19 years later Hong Cheon-gi is a talented painter at Baek-yoo Painting Group and the only female painter of that time. She copies valuable paintings to make money for her father's medicine. Ha Ram has become an astrologer at Seomungwan: government office in charge of astronomy, weather and calendar. He is capable of predicting the future by tracing the movement of stars. He also lives a disguised life as Ilwolseong: the chief of information organization Wolseongdang in order to take revenge on the royal family who had destroyed his family 19 years ago.

After Hong Cheon-gi and Ha Ram reunite, they fall for each other, but the duo is sucked into the machinations of the royal court, particularly those involving two princes: the free-spirited Prince Yangmyeong (Gong Myung) and the cruel, scheming Prince Juhyang (Kwak Si-yang) – a man who longs to become the next king. Their relationship is further disturbed because one of them (Ha Ram) is possessed by the Demon and the other one (Hong Cheon-gi) is the divine painter tasked with making the vessel in which the Demon must be sealed.

• Originally, Park Yong-soon (director of Secret Mother) would direct the series.^[38]
• The first script reading of the cast was held in November 2020.^[39] On July 8, 2021, the site photos of script reading were released by the production.^[40]

In Southeast Asia and Hong Kong, the drama was broadcast on Viu as Viu Original series, premiered simultaneously with Korean broadcast.^[54]

In Japan, the drama was broadcast on KNTV [ko] from February 19, 2022.^[55][56]

In Taiwan, it was broadcast on GTV from April 11, 2022.