Mosswood Dreadknight

If an effect instructs you to choose a card name, you may choose the alternative Adventure name. Consider only the alternative characteristics to determine whether that is an appropriate name to choose.

If a spell is cast as an Adventure, its controller exiles it instead of putting it into its owner's graveyard as it resolves. For as long as it remains exiled, that player may cast it as a permanent spell. If an Adventure spell leaves the stack in any way other than resolving (most likely by being countered or by failing to resolve because its targets have all become illegal), that card won't be exiled and the spell's controller won't be able to cast it as a permanent later.

You must follow the normal timing permissions and restrictions for Dread Whispers when casting it with the permission of Mosswood Dreadknight's triggered ability. You must pay its mana cost (or, if another effect allows, an alternative cost).