Once Upon a Time Season 1 Episode 6 (12/04/11)
-King George wants his son, the Prince to slay a dragon for King Midas in order to save his kingdom, but the prince is killed before he can accomplish the mission.
-Rumplestiltskin had acquired the prince for the king and queen when they couldn't conceive an heir. Unbeknownst to them, he had an identical twin, who is poor and willing to stand in for the prince to save his mother's farm.
-The faux prince actually does kill the dragon. King Midas wants him to marry is daughter Abigail and join the two kingdoms. When the new prince balks, King George says he will kill him and his mother if he doesn't marry Abigail.
-Heartbroken because she will never see him again, his mother gives the new prince a ring which she says will bring him true love and happiness. It is the same ring we see on Mary Margaret's finger in Storybrooke.
-In Storybrooke, David continues to pursue Mary Margaret who avoids his advances until he leaves his wife. Just as she's willing to give her prince a chance, Regina sidetracks David to Mr. Gold's shop where his memory begins to return.
-David decides he needs to give his marriage to Kathryn a second chance, leaving Mary Margaret heartbroken.
-Emma finds Sheriff Graham sneaking out of Regina's house late at night and learns of their affair.