Mission Briefing is a rare Instant card from Murders at Karlov Manor Commander (MKC), collector number 110. Current market price: $0.36, TCGplayer market prices via Scryfall.
Surveil 2, then choose an instant or sorcery card in your graveyard. You may cast it this turn. If that spell would be put into your graveyard, exile it instead. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)