In the opening scene, Jennifer Nelson (Doris Day) dresses up as a mermaid for her father (Arthur Godfrey)'s glass bottom boat tour. Unfortunately, Bruce Templeton(Rod Taylor)'s fishing line gets caught on the zipper of her "tail".

After the fish hook gets caught on the zipper, the camera pans back as Jennifer looks herself over. The camera pulls back so far that you can see a black frame in the top right corner at one point before the scene changes. This frame is a window, which reveals that this sequence was shot in a tank. Esther Willams explains the purpose of these windows in "That's Entertainment! III". These windows allow anybody to see what is going on inside the tank.