It's August of 1931 in Singapore, sixteen-year-old Lim Mei Mei (Ah Mei) arrives at the home of Eminent Mister Lee on the eve of the Hungry Ghost Month. She has been sold to the family as a mui tsai, an indentured servant girl. At the Lee household, Lim Mei Mei's life education begins. There she encounters the spirit of Ah Lian, a mui tsai, who paid the ultimate price for her mistake. Through Ah Lian, Ah Mei discovers the plight of mui tsai, who are both helpless and powerful, and uncovers a shameful secret lurking in the shadows in the Lee house. Ah Mei also meets and falls in love with Hassan Mohamed, an Indian-Muslim and an aspiring poet, breaking every clause in the rule book of love in 1930s British Malaya. She becomes Hassan's Polar Star, and the young lovers must find a way to stay together. Through a twist of fate, Ah Mei finds a solution that will keep her and Hassan together, at the same time gaining agency that will secure her own future as an uneducated servant girl in British Malaya.
