At the beginning of each player's upkeep, that player chooses target player who has more cards in hand than they do and is their opponent. The first player may discard their hand and draw three cards.
The ability can only target an opponent of the current player.
The targeted player having more cards in their hand than the current player is a part of the targeting requirement. A player can’t be targeted by this ability unless it’s true, and the ability doesn’t resolve if it’s no longer true at that time.