In 1997, Louis Theroux made a documentary about the world of male porn performers in Los Angeles. Fifteen years later, he returns to find a business struggling with the deluge of free porn on the internet. Louis revisits some of the original programme's contributors as well as meeting the latest crop of performers dreaming of porn stardom

Louis travels to Phoenix, Arizona - the capital of dementia care. He spends time at Beatitudes, a residential institution, and also with those looking after loved ones at home to try to understand the struggle of living in a world of encroaching shadows - and of keeping relationships alive in circumstances that can be among the strangest and most challenging imaginable.

Louis visits one of the best schools in America for autism. He meets the students and their families to get a glimpse of what life is like for them and to experience the pleasures and the strains of one of the most extraordinary kinds of relationship.