Lulu is Yi Lin's younger sister and a clothing design student financially supported by her fashion model sister. She quietly admires Yi Lin's career and designs clothes for her. However, Yi Lin's demanding schedule strains their bond, leading her to miss Lulu's birthday celebration where Lulu had prepared a special meal.

Following Yi Lin's career struggles and physical collapse, Lulu confronts her sister. She expresses anger over being overlooked and asserts her own identity beyond just a supportive sibling. This confrontation prompts Yi Lin's realization about her misplaced priorities.

Lulu takes initiative to mend their relationship. She designs a red dress specifically for Yi Lin, demonstrating her understanding of her sister's taste and her own design talent. Lulu organizes a surprise fashion show in an abandoned factory, showcasing resourcefulness and dedication to revitalizing Yi Lin's career on new terms. This event marks Lulu's transition from background supporter to active collaborator.

After graduating, Lulu becomes Yi Lin's primary clothing designer. They establish a professional partnership alongside their renewed personal bond. This collaboration allows Yi Lin to regain prominence while fulfilling Lulu's design career goals, forging a path of mutual support and creative synergy.