Three researchers who survived the plane crash entered the valley. The valley is overgrown with very thick forests. All the items they carry are gone and only carry one backpack. Finally they kept walking while hoping to get help. They kept walking between the thick trees. So thick the forest that they could not see the sunlight ... from the gap in the trees. Lush leaves cover the entry of light into the ground. The accuracy of the soil they are on is more moist. Every now and then their bodies are grabbed by leeches. They immediately throw it away so they don't suck blood. If the leech has bitten this animal it will not release the bite. One leech can suck 5 to 15 milliliters, if there are 20 leeches it will certainly be a serious problem.
Luckily they wear long-sleeved shoes and clothes making it safer.
But facing virgin forests that have never been touched by humans is not an easy thing. So many challenges must be faced. They must estimate the day or night. When they feel the cold feels more they believe the day starts at night. So they decide to find a safe place to take refuge. After seeing situation they found a tree that was rather tilted so it was easier to ride. Even more so when they looked up many rather large branches by resembling a nest. this can be used as a place to rest. Finally they decided to climb the tree to avoid the attack of wild animals while sleeping. tired body makes them fall asleep immediately. When they wake up they can see from the tree of sunlight. Finally one researcher climbed to the top of the tree. From the top of this tree he saw a hill in the distance. he immediately went down and invited his friends to continue the journey. They agreed to go there. However, when they saw the river they decided to go along the river. They believe by following the river they will arrive at the estuary. They believe that in the estuary there must be someone who lives. With the survival abilities they have participated in during their training they can continue to survive. They know which plants can be eaten and cannot. They also know flowers that can store water so they can drink it.
After a long period of time they felt the forest began to not be too thick anymore. They feel that they are close to the place where there is human civilization. Finally with difficulty and various obstacles, they reach the river mouth.
Suddenly in the distance there were people gathering. They immediately shouted loudly. This shout was heard by the residents who were at the estuary. They are. come to help researchers who have run out of energy. Finally, the researchers were able to survive after taking danger in a dense forest for several days

Thank you @xpilar
Warm regard from Indonesia