Stu's stag do in South America goes bad when Greg collapses at customs and is found to be full of cocaine. Arrested, the group are taken to an island prison run by cocaine-smuggling siblings, Selma and Branco.

Stu et al watch Clem operate on Ant; Selma learns about a case being built against her; Greg escapes to meet Stu.

Under The Man's instructions, Stu gets the gang jobs in the prison coke factory; Hugo works a special job for Selma involving the assassination of her brother at a dinner being thrown for their boss.

Kai tricks Stu into admitting he put coke in everyone's cases and has a phone; the Man helps Branco see that Selma is behind Davide's murder.

Branco kills Selma; Clem wins a race to the surface and The Monster kills the loser, Gemma; The Man is mortally wounded and Kai gets his revenge on Stu; Stu and Ryan almost make it out together until they don't and Stu's left all alone.