The protagonist, a man in his 30s, lost his wife in an accident and now lives alone with his young son. One night, while working late from home, he notices a strange icon on his desktop labeled “sin.exe.” He tries to delete it, but it won’t disappear. Soon, unfamiliar folders begin to appear one after another. Inside are eerie photos and text files that resemble someone’s diary—but none of it seems to belong to him. Disturbing phenomena begin to occur on the screen, and the protagonist finds himself caught in a digital nightmare with no escape…