Ryoko, a cosmetics saleswoman, accidentally runs over a man, who turns out to be a serial rapist who escaped from a prison transport vehicle. Held captive inside her car by the bloodied man, she seizes an opportunity to escape. Wandering through the forest, she arrives at a mountain cabin where she is rescued by another man. However, he harbors twisted sexual desires of his own. Once discovered, he imprisons Ryoko too...

A woman and her bridegroom are found murdered in their bed the day after their wedding. It had snowed overnight and the killer left no tracks. It is up to an amateur detective to figure out what happened. Carefully and systematically, he pieces together the clues in this locked room mystery.