It's 1986. Esther Rantzen is the face of That's Life!, watched by millions every weekend. Her investigative team is receiving thousands of letters from children suffering sexual abuse, begging for help that no one else will give. With a small group of allies, Esther builds something that has never existed before: a free, confidential helpline, run by volunteers, that any child can call. Told by those who were there, including That's Life! colleague Bryher Scudamore and Colin Butler, one of Childline's longest-serving Counsellors, who answered the phone on the opening night and still volunteers today, to Esther's daughter Rebecca Wilcox, this first episode celebrates how Childline was born in the face of resistance from the establishment. How a BT engineer test number became one of the most famous in the UK (0800 1111)! And how the switchboard crashed as more than 50,000 children tried to get through. We hear how the Helpline quickly grew to listen to children about any concern, fear or hope; anything they want to talk about. We hear from Karen, one of that first wave of children trying to reach out, whose call to Childline, when she finally made it, changed the course of her life. In fact, saved it.

What does it take for Volunteer Counsellors to answer a child 'contact' every 45 seconds? Natalie goes inside a Childline shift: from an early morning briefing to their final debrief. She meets the Counsellors who give their time to listen. Amongst them are Matt, who wrote to Childline as a frightened ten-year-old, and treasured the reply so much he became a Counsellor himself. And Rebecca Wilcox, Deputy President of Childline and Dame Esther Rantzen's daughter, who trained as a Counsellor to carry on her mother's legacy. We learn what twelve weeks of training teaches, and hear about the individual counselling sessions that stay with Counsellors long after they've gone home. Then we step into the Night Service, where the 'high risk' contacts go up and Childline is the only support option a child has. The episode meets Rosa, who at seven stood outside a phone box with the number memorised but never picked up, because nobody had told her Childline wouldn't automatically report to the police. We learn about that unique confidentiality promise, that Childline constantly reviews and fights to retain and its power. Plus, the NSPCC Volunteers visiting primary schools nationwide to ensure that children know the Childline phone number and how to recognise abuse.

Childhood has changed beyond recognition since 1986 when Childline was founded, and the service has evolved with it. In this final episode, Natalie asks who is responsible for keeping our children safe online. On stage at SXSW London with NSPCC Chief Executive Chris Sherwood and members of the NSPCC's Child Safety Online Taskforce, she calls on tech companies to take responsibility for the platforms where children spend so much of their lives. She speaks to Tony Fitzgerald of Kids Helpline, Australia about what that country's under-16s social media ban has, and hasn't, achieved. And we hear from Naomi, who went from contacting Childline to being one of its youngest Counsellors. As online exploitation rises dramatically and AI brings new risks barely yet understood, we discover how Childline is harnessing technology to give Counsellors more time with children. And why, forty years on, the service still depends on volunteers and donations to answer every child who reaches out. Rebecca Wilcox closes with a moving story her mother once told her, that gives a poignant, fitting ending to our three episodes.