When Mary Brown (who has a complex about her looks), goes exploring in the bogs of a small island she's vacationing on, she comes across a downed spacecraft and its alien pilot. The creature asks her to help him free his ship so he can leave, and upon doing so, rewards her by making her beautiful.

NOTE: It should be stated that "plain" Mary and "pretty" Mary pretty much look exactly alike, though I don't think that was the artist's intention.