An adventure, an investigation, a quest ? Matthieu, mountain leader, continues his trekking experience with the Via Alpina, an 8 countries-crossing of the Alps from Trieste to Monaco. One thing in mind : What influence does hiking in the mountains have on us ? Between Matthieu's personal journey and the testimonials of hikers met on the way, a whole new world is unveiled. Far from being just an outdoor activity in a dream-like scenery, trekking becomes an awareness tool driving us to rethink our way of living.