The year is 1982, and as Britain and Argentina go to war over the Falkland Islands, Jack is fighting his own battle with heroin addiction, prompting the former flatmates to help their friend detox. Meanwhile, Lilly receives devastating news, and Charlotte's mother places increasing demands on her daughter, not least when she turns up during an acute manic phase. Penultimate episode of the drama, starring Claire Foy, Sam Claflin, MyAnna Buring and Lee Ingleby.

• Paula Milne

• Jeremy Northam
• Juliet Stevenson
• Ramon Tikaram