Samantha Womack is best known for playing Ronnie Mitchell in EastEnders. Sam's parents separated when she was young, and she grew up with only a fractured sense of her family history. Sam starts her journey by looking into the military career of her great grandfather, Alexander Cunningham Ryan.

Gregg Wallace sets out to solve a long-standing family mystery: what happened to his great-grandfather, Henry Roland Springett, who abandoned his wife and children, including Gregg's grandfather, and was thought to have deserted the Navy?

Sir Patrick Stewart's memory of his late father, Alfred Stewart, is scarred by recollections of domestic abuse. In this deeply personal and moving film, Patrick investigates his father's extraordinary war career, and discovers the shocking impact it had on his character.

Eurythmics singer and political activist Annie Lennox, whose grandmother's father died when she was only three, knows little about this branch of the family. Annie's episode uncovers an extraordinarily dark tale of tangled family relationships blighted by illegitimacy and poverty. On her journey, Annie also discovers the humiliation her unmarried great, great grandmother suffered before the Scottish church.

Comedian and actor Hugh Dennis's grandfathers both fought in the First World War, but rarely spoke about what they went through. In this episode, Hugh uncovers their very different wartime experiences. For his paternal grandfather, Ronald Dennis, the war offered an opportunity to finally escape a life in the coalmines of Yorkshire. For Hugh's maternal grandfather, Godfrey Hinnels, it was a brutal and bloody experience, as he found himself in some of the Great War's most infamous battles.

Actress Alex Kingston knows that her great-grandfather, William Keevil, died during the First World War, leaving behind a wife and young family - including Alex's then 4-year-old grandmother. Alex sets out to investigate exactly what happened to William, and discovers how his pre-war career as a photographer put him in an unusual position. Alex has also heard rumours of Jewish ancestry in her family tree. Her quest to discover if this is true takes an unexpected turn, leading to a story involving her four-times great-grandmother, Elizabeth Braham, another widow with young children. As Alex delves further into Elizabeth's life, she is astonished to discover the unconventional enterprise Elizabeth undertook to avoid sliding into poverty.

Actor William Roache has always known that his grandmother, Zillah Waddicor, ran a cafe in Alton Towers in the 1920s and 1930s, long before it became a theme park. But as Bill sets out to discover more about Zillah, whom he remembers as a kindly elderly lady, he is astonished to find out that the cafe was a far more ambitious enterprise and that, while overcoming a challenging personal life, Zillah was a trailblazing entrepreneur. Bill discovers that his great-grandfather James was also an innovative business person, dealing in some very unusual wares in late 19th century Blackpool.

Actress Celia Imrie knows that she comes from a long line of aristocrats on her mother's side, but has always resisted finding out any more about her illustrious heritage; her fear is that they will turn out to be privileged and boring, but she is quickly proved very wrong. In a film that ranges from political intrigue to impotence, Celia traces her family back to the 17th century. She discovers an ancestor who broke all the rules and ended up in the Tower of London, and investigates the extraordinary political legacy of another ancestor, who was accused of plotting to kill King Charles II.

Fifty years after Jamaica gained independence from Britain, former footballer and sports pundit John Barnes sets out to investigate the extraordinary role his grandfather, Frank Hill, played in the island's struggle for self-rule. John discovers how his grandfather became the subject of secret telegrams, and why he was interned by the British during World War Two. John also uncovers how, from being at the heart of Jamaican politics, Frank fell from grace among his political allies.

John Bishop finds out what happened to his great great grandfather, a POW in the Crimea.