The Nam family leads a life of upper-middle class luxury. Supported by the medical practice of Dr. Nam, the family patriarch, sisters Jung-hee and Myung-hee and their kid brother Chang-sik live in a spacious home, wear fancy Western clothes, and enjoy leisure activities (the mother is absent). The people they associate with are also wealthy, such as Chairman Pang for example, who we see arriving in a Korean Air jet and being met on the airport runway by a limousine at the start of the film.
But this wealth lies on unstable foundations, and when the father dies suddenly, Jung-hee, as the new head of the family, finds herself with steep debts and no source of income. She initially receives a surprising offer of help from Sun-cheol, a young doctor who had previously been supported by the Nam family in his studies. However it's clear that Jung-hee will need to find a job in order to retain the family home and some semblance of their previous lifestyle. Desperate, she turns to Chairman Pang, but the offer he makes is a difficult one: he asks if she will work as a "madame" in his exclusive drinking establishment, joining the male guests at their tables and drinking with them. It's a job to make most upper class girls blush, and to cause the neighbors to gossip, but Jung-hee feels she has no choice but to accept.
A Sister's Garden was made in 1959, and it's interesting to see the improvement in the film's technical qualities compared to A College Woman's Confession, made just a year earlier. Shin had taken the money earned from the latter film's success and invested heavily in film equipment and studio space, setting the stage for his emergence as the industry's most important commercial director of the 1960s. The clear, well-balanced lighting and elaborate mise-en-scene would have been very eye-catching to viewers of the time.
In a more general sense, the film seems to have a fixation on luxury. The 1950s were an era in which material goods from the West first became available in large quantities to consumers, and one of the pleasures of watching this film for viewers of that time would have been to witness the lifestyle of the rich in all its splendour. In fact most all Korean films from the 1950s portray the new material culture and accelerating Westernization of Korean society that was characteristic of that time period. But A Sister's Garden may be the apex of that trend, at the same time as it displays an interesting love-hate attitude towards the capitalist direction in which (South) Korea was headed.
Meanwhile, an unexpected surprise in watching this film for modern fans of Korean cinema is the presence of "national actor" Ahn Sung-ki (A Battle Of Wits, Nowhere To Hide) as a seven-year old boy. The character of Chang-sik adores his older sister Jung-hee and eventually builds a camaraderie with Sun-cheol, who harbors a helpless love for Jung-hee. Although it seems that Ahn's voice has been dubbed in this film, it's interesting to see such a well-known actor at such a young age - even younger than when he appeared in The Housemaid.