Serenade of Peaceful Joy, or previously known as Held in the Lonely Castle, is a 2020 Chinese period drama series loosely based on Milan Lady's novel of the same name. It is directed by Zhang Kaizhou, and stars Wang Kai as Emperor Renzong of Song and Jiang Shuying as Empress Cao. The series aired on Hunan TV starting April 7, 2020.

Wang Kai is a Chinese actor. He is known for his television roles in All Quiet in Peking (2014), The Disguiser (2015), Nirvana in Fire (2015), Ode to Joy (2016), When a Snail Falls in Love (2016), Stay With Me (2016), and Like a Flowing River (2018), as well as his film role in The Devotion of Suspect X.