He plays Hubert Hawkins, a refugee from a carnival who falls in with a Robin Hood-type fellow called the Black Fox. Set in some mythical medieval era in England, the rightful king was ursurped and the true heir, a baby with the purple pimpernel birthmark on a butt cheek, is being transported by the Black Fox's men. Or in this case, right hand woman, Maid Jean, played by Glynnis Johns. She and Hawkins set out in diguise to get the baby to safety and find that they might be falling in love, if Hawkins wasn't such a drip of a guy. But he will show his courage in this silly but wonderful plot.
They discover a Jester on his way to court and Hawkin's takes his place. In the meantime, evil Lord Ravenhurst (played straight by Basil Rathbone in his Robin-Hood-Nemesis-kind-of-role) has hired the Jester, who is really an assassin, to kill his rivals. Angela Lansbuy plays the king's daughter who is looking for romance, not a marriage with the crass Griswold and sends her maid and witch Griselda (played by Mildred Natwick) to scotch those plans.
The Jester ends up insulting Griswold but in order to assauge his honor properly, the Jester must be knighted in one of the funniest scenes in cinema history.
The songs are great, the jokes fantastic (who can forget lines like: "The pellet with the poison's in the vessel with the pestle; the chalice from the palace has the brew that is true!"), and the Technicolor a feast for the senses. But apparently, even though this was the most expensive comedy to date and Kaye was at the top of his game, the movie when it was released in 1956 was a flop. It gained new life and a cult following on television, though.
Is it medieval? Not in the sightest. I love it anyway.
Some great moments (watch the videos): The Maladjusted Jester Song