Just watched the series for a second time having seen it when first released in the USA. Even better the second time!
Beautifully acted, directed, cast and written. Disregard the critics' carping about a predictable story. They all miss the point, i.e., the characters' coping with, and reacting to, the "predictable" circumstances. Hattie Morahan as Rose provides an especially brilliant and convincing portrayal. Her sister gives a heart-breaking performance. The boy, (narrator), is inspired casting. Overall, this is a truly wonderful series with great acting and direction that, as usual, only the UK can deliver. At some point, I know I will watch it again! Pity there was no follow-up season.