Carchar y Glannau, ac mae carcharor, Barry Hardy, yn codi bag o gyffuriau oddi ar y llawr ar ôl i rywun ei ollwng - penderfyniad sy'n mynd i newid ei fywyd am byth. Er bod ei gymar cell, Peter, yn ceisio ei berswadio i gael gwared â'r cyffuriau, mae gan Barry syniad. Mae digwyddiad gwaedlyd ar y wing yn golygu bod y swyddogion, Elin a Ned, yn poeni am eu swyddi. Ac mae carcharor newydd yn cyrraedd. Dyw Kit Brennan ddim yn wyneb newydd i bawb, ac mae ei ymddangosiad yn peri gofid i fwy nag un.
Location: HMP Y Glannau, and prisoner, Barry Hardy, picks up a bag of drugs off the floor after someone dropped them. A decision that is going to change the course of his life forever. Although his cellmate, Peter, tries to persuade him to get rid of the drugs, Barry thinks he knows better. A bloody incident on the wing means that the officers, Elin and Ned, worry about their jobs. And a new prisoner arrives. Kit Brennan isn't a stranger to everyone, and his appearance disturbs the equilibrium.
