 King Jozef goes on pheasant hunt, that is he sits outside and orders his  hounds , the Grimms, to chase the fowl his way, so he can shoot it, and then fetch. However the Mother of the Devil takes her all too good boy to her own mother (grandma devil, hence the title), who manages more powerful spells, enough to turn Kulderzipen into a duck. The Grimms discover angels can force grandma, so they dress up with wings -hence the king takes them to play pheasants-and convince her by uttering some English words (in Dutch, the word for angel is that for English minus the terminal genitive -s).