The journey starts from the forest ranger station in Montarbu, a beautiful place provided by the Forestas company for overnight stays, which must be booked a few days in advance with the management in Lanusei. The site is well equipped, and among other things, you can refill your water supplies. You walk on a dirt road, and after about 800 meters, you cross a gate and continue along a well-marked path with the railway to your right. Currently, the little green train that operates that route is not active due to maintenance work on the "su irtzioni" bridge, located 800 meters ahead. The path continues on a dirt road parallel to the railway, through the forest, and after about 2 km, it opens into a large clearing with a picnic area and a small building in need of restoration. Further ahead, by deviating left for about 300 meters, there is a lovely spring called "funtana de sa berda". The path continues downhill, and with a couple of bends, you arrive at the river "Riu sa taula", which you cross near a beautiful natural pool with a small waterfall. You then proceed uphill along the river, rich in features, including a large limestone formation resembling a tortoise. After about 1 km, you reach another picnic area in the locality of "Tuvu Nieddu", where a rich water spring flows. You cross the river and continue on a dirt road until you reach the bar restaurant, a beautiful equipped area that is not open year-round, near which there is also a stop for the little green train, called "Stazione di Niala". The Sentiero Italia continues to the left with a steep ascent, partly paved. On the right, halfway up, deviating from the path, there is a work by the famous artist "Pinuccio Sciola" depicting 6 limestone balls with a diameter of 80 cm; there is also water and a picnic area here. Re-entering the path, still in the woods, you arrive on a plateau where a dirt road takes you, after about 5 km, to an archaeological area of particular interest called "is Tostoinus". You can admire a nuraghe and a giants' tomb. Further on, crossing a stream via a very beautiful wooden bridge, you reach a picnic area with water and a well-maintained small building that could be used as a shelter in the future. Exiting this well-maintained area by Forestas, the ascent begins to reach the ridge. Here the mountainous and arid terrain makes the path particularly challenging during the summer. After about 4 km, the descent towards the end of the stage begins along a well-cleared and very panoramic path that borders the entire valley. Arriving at Gairo Taquisara, a small and beautiful village with 300 inhabitants located at the foot of a valley full of oaks and fir trees, it is possible to stay at hotels or B&Bs or refresh at the bar. A very beautiful stage, not too long, amidst the woods of "Tonneri di Ussasai-Seui", shaded and well supplied with springs.