Arthur Brennan, an adjunct physics professor, travels to Aokigahara ("The Suicide Forest") with a sealed package. Once there, he attempts to end his life via drug overdose but encounters a Japanese man named Takumi Nakamura. Takumi entered the forest two days prior and slit his wrists for being demoted at work, but soon realized he would miss his wife and daughter. Since then, he has tried to escape the dense sea of trees but cannot find the trail back. Arthur decides to help but the two end up disoriented and lost. To keep their minds occupied, they share details about their lives, including the names of Takumi's wife and daughter: "Kiiro" and "Fuyu."