Kamaitachi no Yoru follows Tōru and his girlfriend Mari as they become embroiled in a murder mystery while on vacation at a skiing lodge. The player must gather clues to solve the crime before it's too late, with additional murders committed if they're slow to collect evidence.
The gameplay involves reading still pictures with text covering the entire screen, making choices, and pointing out the murderer. Clues are often misleading, and true evidence is hidden in nonsensical places within ridiculous dialogue.