Take Two Aspirin and Half a Pint of Porpoise Milk
As a result from a black Peruvian rose, Samantha starts getting sick and loses her powers. She ends up getting green spots all over her face and needs a remedy with a rare ingredient, an ostrich feather. Just when you think that getting the ostrich feather was all they needed, it turns out that they also need the petals of the dreaded rose to make Samantha feel better again.