Fenner adjusts to life on the inside, whilst Tina adjusts to life on the outside. Grayling plans to turn G Wing into a flagship for change in the prison system. The Julies catch Ben kissing Buxton. Two new inmates arrive at Larkhall.

BAD GIRLS is a powerful drama series set in the closed world of an English women’s prison, HMP Larkhall. BAD GIRLS has hard-hitting, heart-wrenching stories that get down and dirty with life behind bars, never shying away from the gritty side of life. On the inside they must negotiate their place in the prison’s hierarchy and sometimes make new sexual choices.

Zandra gives birth and battles with her addiction, putting her future with her baby at risk, she climbs on to the roof in protest. Fenner gets his feet under the table as Wing Governor only for Helen to return and cut his reign short. Shell continues to torment Fenner's wife and has a mobile phone smuggled into the prison.

The new deputy governor is late for work on her first day. New inmate Emira, a suspected muslim terrorist, is soon put to work by Buxton. PO Kimber is transferred from D Wing.

Six weeks after Yvonne's escape attempt and Kris follows in her footsteps but makes a grisly discovery. Two new inmates arrive, one with a secret more deadly than the other. Collin spirals out of control and relapses. Fenner begins to unravel as his dark secret begins to come to light.

Fenner and the Larkhall screws visit Amsterdam for a dirty weekend. With the mystery firearm still missing, G Wing remains in lockdown. Snowball is released from solitary, and Denny is out for revenge.

Virginia's murder investigation begins. Karen suspects the mounting number of allegations against Fenner may be true. Yvonne takes desperate measures with the help of Josh and the two Julies.

G Wing is in uproar after Shell stabs Fenner then barricades her cell door. Helen tries to persuade Nikki to return to Larkhall instead of absconding.

とある事件がきっかけで教師の職を辞した井沢圭吾（玉山鉄二）。大学時代の先輩で、東南アジアの小国SERAIVIAで孤児院を経営している譲原（中村俊介）を訪ね、しばらくは孤児院を手伝うことに。そんな中、譲原は資金を提供してくれるというジョイという男の口車に乗せられ、全財産を失う。怒った圭吾はジョイに金の返却を求めるが、警察に裏金を払ったジョイの策略により、逮捕されてしまう。獄中で絶望に陥っていた圭吾は、同房の謎の男ポン（大森南朋）から脱獄計画を持ちかけられるが…。

犯下杀人罪入狱的前警察申世道报名参加了监狱内部秘密搏击游戏，在巨额赌注的诱惑下 ，监狱长甚至漠视杀人。在那里申世道发现了杀死妻子的真凶，他决定不…