Once Upon a Time

In the past, Arthur threatens to tear his marriage asunder in his quest to restore Excalibur. Meanwhile, Guinevere and Lancelot enter the Dark One's Vault to find the Dagger, and Guinevere is forced to make a deal with Rumplestiltskin. Six weeks earlier in Camelot, Mary Margaret and Lancelot prepare to hide the blade, but discover that Arthur has an unexpected ally.