Guess Who Killed My Twelve Lovers?

噴火美人魚 (original title)

Synopsis

Six guitar playing, rock and roll singing and dancing young people on a boating trip are stranded on a rural island off of Hong Kong during a typhoon. They become suspicious of a woman who matches the radio bulletin description of a murderess who killed twelve men. Can she be trusted? Is she laying a trap for a local youth housesitting a mansion?