Zoë, Ylena and Michiel meet again on the birthday of their friend Lisa, who disappeared five years earlier on her trip from Rotterdam to Nice. Lisa's disappearance has never been solved.

Zoë, Ylena and Michiel travel through the Netherlands and Flanders. Pete travels at his own pace. The road evokes many memories of Lisa. The subcutaneous tensions become palpable.

The group has fallen apart now that Asim has turned up. When spending the night in Spa at Pete's cousin's house, it becomes clear that Lisa's stay there during her trip was traumatic. Zoe gets to know a German hiker.

Ties with Asim are re-established along the way. The French border region turns out to be by no means the most beautiful stretch of the GR5. Pete rides along with Bart and Storm and makes another disconcerting discovery about Lisa.

With the traumatic events on the Col du Donon, the memorial ride seems dead and buried. Pete moves on to Le Grand Ballon on his own. Together with inspector Pol Martin, he searches for the spot where Lisa was last seen.

Pete is in all states now that it turns out Asim visited Lisa on the road. He accuses him of doing something to Lisa, but Asim denies this. Karen drops by and feels especially responsible for her daughter's grief.