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Karen, Piet and Michiel visit the architect in Chamonix who is said to have hiked with Lisa. He tells them Lisa's destination: a reservoir in the Maritime Alps. She is said to have worked in a guesthouse there. Once there, they receive terrible news, and Lisa's parents Karen and Piet decide to make their way back.

Ylena finds out in hospital that she has a tear in her meninges and her life is in danger if she doesn't have an operation. But Ylena isn't sure if she wants to live at all. Zo

A witness turns up in the French Jura. She claims to have seen Lisa at a waterfall. And indeed, Lisa's rucksack can be seen in one of her photos. Is this captured moment a clue to her suicide at the waterfall?

Lisa's father Piet decides to go alone to the Vosges, where he last saw Lisa. It was there that he told her in an argument that Karen was not her mother.

The friends hike through Lorraine and approach Alsace, where Lisa has disappeared. Piet takes every opportunity to question people who may have seen Lisa. This is how he finds out that Ylena's husband Bart met Lisa back then without Ylena's knowledge.

The trail leads the hikers onto the small Belgian town of Spa. Ylena, Piet and Zo? spend the night there in a hostel run by Piet's cousin and his wife. Lisa's mother Karen also comes to visit the group. What was planned as a happy reunion ends in a big argument over dinner.

The first few days of the hike are tough because the weather is bad and the heavy rucksacks are still unfamiliar to carry. In addition, Zo? has decided to stop smoking, and the others suffer from her bad mood.

Five years ago, Lisa disappeared without a trace on the GR 5 long-distance hiking trail. Only her travel diary turns up later. The police suspect suicide or a violent crime. Her parents and friends have not got over the loss. Lisa's mother, Karen, cannot come to terms with the fact that her daughter has disappeared. She firmly believes that Lisa is still alive.