This Korean adaptation is  based on the original Chinese novel, "BubuJingXin" by Tong Hua, and on the original Chinese drama. 

This is a very brief summary of the novel  by Tong Hua. I will link later where to read it ( partly in English, partly only in Chinese).
In the link i post here, there is a brief analysis of characters comparing to this upcoming Thailand adaptation,
and then a summary of the novel in more specific details.

https://x.com/QueenSNabila/status/1783316601011585084