The last time Glenda Jackson starred in a miniseries on this umbrella series that imports dramas from the U.K., the series was called Masterpiece Theatre, and Jackson starred as Elizabeth R in 1971 – the very year that Masterpiece Theatre launched on PBS. Now, 50 years later, the series is called simply Masterpiece, and Jackson is playing a woman looking for her missing best friend – while, at the same time, slipping deeper into dementia. Check