At the start of my turn, I have no cards and my opponent has 10 cards. At the end of the turn, I have 10 cards and my opponent has no cards. What happened?
One can assume that before trashing your deck, you have managed to accumulate many coin tokens.
So by using Traveling Fair, buy two King's Courts, a Thief, a (1st edition) Masquerade, and Mission.
Play KC-KC-Thief-Masquerade.
Opponent has all 10 Scepters; five in hand, five in deck.
The Thief trashes 3 Scepters and gains them.
The Masquerade draws the Scepters and exchanges them with the opponent, without trashing any.
Now play two Scepters to replay the Thief twice and trash the rest of the opponent's deck. Do not gain the Scepters.
Play the remaining Scepter to replay the Masquerade. Receive a Scepter from the opponent. Repeat four times.
Buy Bonfire to trash two cards and you're left with ten cards.
The drawback is that this does not work with 2nd edition rules for Masquerade. But there are many variations that can be substituted.
KC-KC-Thief-Torturer. Torturer will draw the first three Scepters and force the opponent to discard his hand. Replay Thief and Torturer as needed to gain/draw the remaining Scepters.
I particularly like a variant that forces him to trash all of his Scepters, then you play a Treasurer which can gain one to your hand. Rinse and repeat.