"Although Aunt Lan married Father, she remained childless due to health reasons. Now that Father is gravely ill, several uncles have started to vie for the family inheritance, and Aunt Lan has finally revealed the truth to Father."
"What truth?"
"In fact, Aunt Lan knew early on that she was infertile, so she intended to make way for Father and Mother. However, knowing Mother's temperament, she wouldn't take something loved by another. Thus, Aunt Lan spiked the wine, thinking that once they had a relationship, Father would take responsibility for Mother. However, she didn't expect Mother's strong-willed nature; feeling guilty, Mother left behind a letter and disappeared."