William Miller's moving portrait of his father, whose extraordinary and unique memory would eventually be stolen by the thing he feared most - Alzheimer's.

Broadcaster and director Sir Jonathan Miller, one of the greatest minds of his generation, believed the most important cognitive function humans possess is memory. Without it, you can't learn or know who or where you are. Without a functioning memory, you wouldn't be able to recognise, recall or retrieve a thing. In fact, without it, you simply wouldn't exist.

Tragically, Jonathan died of Alzheimer's in 2019 before he got to make the one series he'd always wanted to present on the workings of human memory.

In this programme, William Miller embarks on a journey to uncover the story of his father's life as told through his extensive archive, and pieces together the documentary Jonathan was going to make with his producer, Richard Denton, that would have explored memory - what it is, where it is and how our memories define us. He talks to family and friends who share their own memories of Jonathan, including his Beyond The Fringe co-star Alan Bennett. And he seeks to learn more about Alzheimer's, the disease that killed his grandmother and father and still haunts his family today.