Back to the beginning: Hubert Hawkins is a carnival performer with a travelling band of acrobats and jugglers who are really part of a group of revolutionaries (of the Robin Hood variety) hanging out in the forest. They are led by a stalwart type known as The Black Arrow. Their aim is to overthrow the corrupt King Roderick I (Cecil Parker), by putting the rightful king - who happens to be an infant - on the throne.
To that end, Hawkins travels - disguised as Giacomo, a Court Jester (King of Jesters and Jester of Kings) - to the King's castle with Maid Jean (Glynis Johns), on an errand to pick up the baby (with the mark of the Purple Pimpernel) who is being hidden by loyalists within the castle's walls. On the short trip, Jean and Hawkins grow closer, though she is leery of his bumbling. Of course, this being a Danny Kaye film, nothing goes right in this great script written by the fabulous Norman Panama and Melvin Frank who also directed. The tongue-trippingly, saucy songs are once again written by Danny Kaye's wife, Sylvia Fine, and once again they require the dexterity of a genius to perform. Luckily, Kaye is one.
The plot is further complicated when the Princess Gwendolyn (the King's daughter, played by Angela Lansbury) falls for Hawkins almost immediately despite the fact that she is already betrothed to the odious Sir Griswold (Robert Middleton). In the meantime, her maid Griselda (Mildred Natwick) who is also a part time witch and hypnotist, overhears Ravenhurst and his two cohorts John Carradine and Michael Pate conspiring to use the Court Jester/Assassin to further their ends. Griselda then hypnotizes Hawkins into believing he is the assassin once she snaps her fingers. Unfortunately the same thing happens when anyone snaps their fingers. One snap: he's the assassin. Two snap: he's the timid Hawkins once again.
Okay, so the princess thinks she's eloping with Hawkins at midnight and the evil Ravenhurst thinks the three knights will be dead at the stroke of midnight and Hawkins is unaware of any of this since it all occurred while he was under hypnosis.
But later that night, Ravenhurst is convinced Hawkins is an assassin par excellence when the poison brews find their marks (thanks to Griselda) despite the Court Jester's ineptitude.
As part of his 'jesting' duties, Hawkins must sing a song for the King and his court. He performs a song about his 'work' as a jester, the last line of which is unforgettable: "...for a jester without employment is NOBODY'S FOOL...!!!" Sylvia Fine's lyrics have never been funnier or wittier.