1950 年代末，日本禁止卖淫，如果发现一名妇女从事这一职业，她们就会被送往感化所。 这是一个关于勇敢的女性国子从感化所被释放并试图开始新生活的故事。

"The third film in the series, The Trap, is an unusual beast. When the film opens our perpetually down-on-his-luck hero is actually on a bit of a roll. Business is booming, he’s got a new girlfriend, Akane has been accepted into college … he’s even upgrading his office equipment. Things couldn’t be better, right? Well, it wouldn’t be noir if things went well for Hama and the story takes a dark turn when a mysterious masked figure arrives in Hama’s office and asks Maiku to follow and find him. Thniking the visit a prank, Hama ignores it. But soon bodies begin to turn up throughout Yokohama and when one of the corpses has Hama’s fingerprints on it he soon finds himself on the run from the police while trying to unravel the mystery …
The Trap is simultaneously the darkest and the lightest of the bunch. With its tale of serial killers and mental illness, not to mention some of Hama’s closest friends taking some serious damage, The Trap certainly has the grimmest storyline of the three films. But, on the other hand, it also features a masked villain straight out of low budget serials, a fantastic sequence in which Hama’s mentor – played as always by Jo Shishido – gets to rally the troops, and a little bit of spy gadgetry. The Trap tries to play it both ways and does a surprisingly good job of it. The dark elements ratchet the tension up while the lighter parts keep things hopping along." - Twitch Review

弁護士界の大物・西垣が拷問の後に殺害された。事件の担当になった横浜地検の検事・美紀子（黒木瞳）は検察事務官の伊藤（布施博）と共に捜査を開始。事件を解決するために協力を求めようと神奈川県警の郡司刑事（ガッツ石松）のもとを訪れる。当初、美紀子を見下すような態度をとる郡司だったが、次第に協力者となっていく。その矢先、西垣が検事出身の弁護士や実力派の弁護士を敵に回していたことが発覚し、
美紀子は日弁連本部の強制捜査令状を申請する。しかし、美紀子は上からの圧力で担当を外されることになり、その直後に西垣の秘書官から秘密の資料を渡される。その後、秘書官は殺され美紀子も拉致される。

他の娘と結婚した無情な男の新居に放火した女、前科11犯の窃盗犯、年若い夫を殺して乳幼児を抱えた女など、女子刑務所囚人たちの様々な生態を描き、その矯正補導を主題とした異色の社会派ドラマ。木暮・久我・岡田・香川らが女囚人を好演。