Series-8 of (the new) Doctor Who is the weakest since the show was revived in 2005. Some have blamed this on the new lead actor, Peter Capaldi, but he plays the Doctor as well as anyone could given the poor quality of the writing of some of the episodes, combined with the exceedingly dark tone of this season (or series in Britain). That said, there are several very good stories, such as "Robot of Sherwood" and "Time Heist". "Deep Breath" and the 2-part finale "Dark Water" / "Death in Heaven" were also pretty good. The episodes that I consider real clunkers are "Kill the Moon", where Earth's Moon turns out to be a giant moth egg infested with giant spiders, and "In the Forest of the Night" which has more plot problems than I can to cover in short review. For those, I'm only giving the series set 4-stars. Thankfully, series-9 is better. I'd recommend series-8 on Blu-ray, but with some reservations.