Chie and her twin sister attend school with Mao Lan, initially posing as her admirers. They engage in frequent playful teasing directed at Mao Lan's perceived naivety and cheerful nature, maintaining a false front of supportive classmates who enjoy her company.

Both sisters participate in the Prime Mat experiment as "main cast" actors. Unlike expendable "extras," they retain full awareness of the experiment's fabricated reality and receive protection from its threats. Their true personalities starkly oppose their on-screen roles: self-centered, cruel, and exhibiting extreme ruthlessness. They joined the experiment under an agreement guaranteeing erasure of their unspecified criminal records.

Growing impatient with the experiment's progression, Chie and her sister defect from protocols to expedite their exit while securing participation benefits. During Mao Lan's psychological breakdown upon discovering her existence's truth, they openly mock her distress and express visceral disgust toward her true nature. Their defection culminates in violent deaths at the series' conclusion.