Swirling mystery permeates Sea of Trees as Bill, an American college student, and his Japanese girlfriend Junko traverse the Aokigahara Forest in Japan-infamous as one of the world's top suicide destinations-in search of evidence of Junko's sister Izumi who disappeared there a year previous. As the two follow clues and journey deeper into the woods amid the eerily quiet and hauntingly beautiful landscape-bypassing tokens and remains of the departed, suicide notes tacked to trees and shrines put up by forlorn loved ones-they'll depend on one another in ways they never had to before, testing the very fabric of their relationship. And, as daylight quickly escapes them and they find themselves lost in the dark veil of night, Bill discovers a truth Junko has hidden deep within her-a truth that will change them both forever.