Bert narrates the story of the young King Gerard (played by Ernie) who could not whistle, which disappointed him greatly as he enjoyed all kinds of whistling. He becomes so discouraged by his inability to whistle that he stops trying, and he officially rules that no one else in the kingdom can whistle. As a result, the birds start croaking like frogs, the Royal Grocer plays her trombone (tooting out "The People in Your Neighborhood") while she goes about her business, and the Royal Policeman uses the sound of a drill to help direct traffic.
After a while, King Gerard's sister Princess Kathy has a stern talk with her brother about the no whistling rule, saying that he should have kept trying. After giving it some thought, King Gerard revokes his ruling, restoring things to the way they were before. King Gerard decides to give whistling another try and eventually can whistle beautifully, so much so that it starts to grate on Princess Kathy while she studies. King Gerard whistled happily ever after.
In addition to Frank Oz and Jim Henson performing Bert and Ernie, Oz and Jeff Moss voice two birds who decide to croak instead of whistle, and Henson voices the Royal Policeman. Moss' then-wife Marian Hailey-Moss voices the Royal Grocer and Princess Kathy.