A TV drama about school bullying sparks public panic upon release. The screenwriter, Jing-zhi, becomes a victim of online abuse and falls into depression. For her well-being, Jing-cheng plans to take her abroad, but a tragic car accident leaves him in a coma for three months. Upon waking, he learns the driver received a light sentence and suspects foul play, especially as his parents begin being followed. Realizing the law can’t help him, Jing-cheng forms a vigilante group operating in a legal gray zone called “Dark Fern.” Using cinematic methods, he immerses wrongdoers in scenarios mirroring their victims’ trauma, forcing confessions. His first two cases link back to Jing-zhi’s death and the mysterious demise of actress Xiao-yu’s younger brother, drawing police attention to “Dark Fern.” As Jing-cheng closes in on the truth, he makes a shocking discovery: everything has been part of Jing-zhi’s meticulously orchestrated plan for revenge.
受到網路霸凌的編劇靜芝罹患憂鬱症,景城本打算帶靜芝出國,卻慘遇車禍。昏迷三個月後,景城發現法律輕判肇事者,父母也被跟蹤。深知法律無法幫他,景城成立「暗蕨」組織,利用電影手法,讓加害者沉浸於相似情境使他們認罪。先後兩起案件都跟靜芝和演員筱妤的弟弟死亡有關,引起警方關注。景城卻漸漸發現這一切都是靜芝策劃的復仇計謀。