The Federation Starship Sceptre is trapped by the Klingons after accidentally straying into Klingon space.  In order to free the ship one of the crew has to beat the Klingons' local female champion in a one to one fight.  After the first challenger ( the Sceptre's female Security officer) is totally thrashed by the Klingon, a ship-wide call is put out for a volunteer to face the Klingon.  To everyone's surprise one of the Sceptre's cooks comes forward.  He's a big ugly Mandork who claims to have been a professional fighter before he became a cook.  He says he has defeated many Klingons in his fighting career and would be only to pleased to dispose of this one.

So the a few hours later the Klingon and the Mandork are beamed down to the surface of a remote planet to engage in naked combat.