Fukami, a secretary engaged to company president Kaido, her employer, is invited by his close friends, the Nogis, to a three-day-two-night tour. The tour group is traveling in a luxurious coach to Lake Megami in the Tateshina Plains. On the way, they are disturbed to hear that Shirai, a hostess who was supposed to come along on the tour, has been murdered. And the next day, the body of Hasegawa, another tour member, is floating in Lake Megami...
| Actor | Role |
|---|---|
 Wakiko KanoChizuko Fukami | Chizuko Fukami |
 Yūki MeguroMasayuki Nogi | Masayuki Nogi |
 Rumi MatsumotoAkiko Nogi | Akiko Nogi |
| YYasuhiro AraiNaoya Yashiro | Naoya Yashiro |
 Miyuki TanigawaMiyako Matsumoto | Miyako Matsumoto |
 Chieko MatsumotoMari | Mari |
 Yukiko TakabayashiTomoe Hasegawa | Tomoe Hasegawa |
| TTomoko HirasawaSumiko Shirai | Sumiko Shirai |
 Akira IshihamaDetective | Detective |
 Koichi UedaFujishima | Fujishima |
 Yū NumazakiDetective | Detective |
 Mamoru TaguchiDetective | Detective |
| RRikiya IwakiNot listed | Not listed |
 Minoru HiranoAssistant inspector Tadokoro | Assistant inspector Tadokoro |
 Saburo ShinodaTakafumi Kaido | Takafumi Kaido |