Bastard of Bolton 's passive ability says: If a card would be discarded from an opponent's hand or deck, instead put it into its owner's dead pile.

Plot effect on Scouting the Pass says: Intrigue Gambit. Any character card that would be discarded from an opponent's hand as part of the claim of an intrigue challenge may be put into play by the winner of the challenge, under his or her control.

So what happens with this combination on the board?

1st player determines order of passives and would get to pick which one happens first.