The Plot "Men of Pride" states

"non-unique cards lose all keywords"

Does this plot effect cards that are not in play ?

In particular does it impact my ability to use the Ambush keyword on non-unique cards in my hand ?

Unless a card specifically says otherwise, it only affects cards that are "in play." Men of Pride will not take Ambush away from non-unique characters until they are in play, and at that point, so what?