Heo Su-A was born into a poor family and sold to the Yeo household to work as a maid at five years old. When she grew older, she became Yeo Yunhwa's handmaiden. 

The year is 1926 in this retelling of Hans Christian Andersen’s “The Little Mermaid”, and Joseon (present-day Korea), is under colonial Japanese rule. Su-A Heo is a handmaiden who spends her days working and swimming in the sea. Her work is her whole life, until one day, when she discovers a wounded independence fighter named Ui-Hyeon Kang washed up on the shore. She nurses him back to health, only to lose her ability to speak in a botched murder attempt by Ui-Hyeon’s comrade, Hae-Su Song. As she travels to the capital, Gyeongseong (present-day Seoul), to get revenge, she finds herself growing more and more intertwined with a strange, brave new world and the people within it. (Source: WEBTOONS)
 
Note: Chapter count includes prologue.