As Fang's solo investigation raises more suspicion about himself, Hsu receives an unusual job offer from the Sevenleaves Foundation.

The search for a deserted bus brings the police one step closer to the truth. Fang and Hsu grill Ming-cheng about what happened 15 years ago.

Following clues from an old photo, the police track down a man named Wu Chun-lu. Later, Fang runs into Hsu at Sevenleaves.

While Hsu starts to question Lin Ming-cheng's integrity, Fang discovers more unsettling leads that point him toward someone he admires.

The investigation reveals a link between the serial killings and a past crime. Fang disregards Hsiao-meng's efforts to help solve the case.

The emergence of a new suspect dramatically redirects the investigation, forcing Fang to race against the clock to locate the serial killer.

After attending a mentor's funeral, Fang returns to the police station and finds himself embroiled in two murder cases that happened 15 years apart.

With his life at stake, Fang needs to survive a deadly encounter. Meanwhile, Hsiao-meng and Hsu must risk everything to save their loved one.