Subtitle: A Confession of the Mask(仮面の告白)
During the trial for Shigeru Kuroiwa(黒岩 繁), a suspect for the serial monster mask robbery case, Kaori Mutō(武藤 かおり), the lawyer for the defendant, discovers that Sergeant Kaoru had illegally obtained a key piece of evidence for the prosecution, a Frankenstein's mask matching the description given by the robbery victims. She then continues her questioning to discover that Sergeant Kaoru forced Shigeru to a nearby police box involuntarily and illegally. Because the fourth monster mask robbery had just taken place, Shigeru was then transported to the Tokyo Metropolitan Police Department, even though the police didn't have definitive evidence that Shigeru committed that robbery.
As a result, Shigeru is found innocent and freed from jail. Sergeant Kaoru and Sergeant Itami are still convinced that Shigeru is the culprit, and they secretly stake out Shigeru's apartment.
Inspector Ukyō also starts his own investigation, and after going back to one of the earlier crime scenes, he visits and questions one of the victims again. Ms. Mutō also shows up at the victim's residence, apparently hoping to find definitive evidence that Shigeru is innocent. There they hear that the robbery victim may have injured the masked attacker when she kicked him as hard as possible.
Meanwhile, the two sergeants staking out Shigeru follow him to a restaurant where, to their surprise, Miwako shows up to interview him. At one point during the interview, she asks Shigeru if he is the culprit. This sets him off and he throws a cup of water in her face. Shocked, Sergeant Kaoru rushes up to them from his hiding place, but in the process, let's Shigeru know that he's being watched.
Even so, the two sergeants continue their stakeout, following Shigeru's back to his apartment. Some time later, a fifth robbery is committed by a man wearing a Frankenstein's mask. Soon afterwards, the two sergeants rush up to Shigeru's apartment and confirm that he in his room.
Is Shigeru guilty or innocent?
Other characters appearing/mentioned in the story
Yoshiyuki Miyagi(宮城 義之) - prosecutor for the case
Kōken Onoda(小野田 公顕) - The superintendent supervisor visits Inspector Ukyō in the Tokumeigakari office to let the inspector know that he is investigating a big case and that he's hoping that the inspector would help him solve that case. The Tokumeigakari pair investigates that case at the end of the season.
