Mark Cobden is sent to prison and has to learn quickly how to survive; when an inmate identifies prison officer Eric McNally's weakness, he faces an impossible choice.

Fellow inmate Johnno bullies Mark, who is unsure if he should tell the prison officers and be labelled a grass or risk the attacks becoming more and more violent; Eric's son is attacked.

Mark suffers a tragic personal loss and is able to leave prison for a day; Eric has to take greater risks to protect his family.

Three women are pulled into each other's orbit when they arrive at Carlingford Prison on the same day. While single mother Orla fights to keep her children out of care, young heroin user Kelsey is presented with a life-changing decision.

After six months outside, Orla finds herself back in Carlingford, and desperate to maintain contact with her kids, she's willing to risk extreme action; Abi contemplates revenge and Marie-Louise encourages her to open up about her past.

Orla faces the consequences of her actions and suffers a personal loss while still struggling to reconcile with Kyle; with the support of Kelsey and Marie-Louise, Abi finally starts reckoning with her unresolved grief.