"Rollings Reliable" is sponsoring an essay contest to honour the mothers of the town. When Sara decides that Aunt Hetty should be her subject for the contest a scornful Sally Potts and Felicity tell her only a "real" mother could be entered in the contest. Having found out that Sally and Felicity share a birth date, and were delivered by the same doctor, a mischievious Sara tells them they were switched at birth. Both girls and their mothers agonize over this and learn that it is "who raises the child, and not who gives birth" that makes a woman a mother. Felicity enters Sara's discarded essay in the competition and Hetty wins. (thetvdb.com)