If an opponent would search a library, that player searches the top four cards of that library instead.
4/18/2017 Each search works exactly the same as normal except that the opponent doing the searching sees only the top four cards of that library. He or she can’t look at the other cards in that library at all. Cards not in the top four cards of the library can’t be found in the search, even if they’re identifiable in some manner.
4/18/2017 For effects that check whether a player searched a library, searching the top four cards of that library counts as searching that library.
4/18/2017 If an effect uses the word “search” once but allows an opponent to search for multiple cards, the top four cards remain the same throughout the entire search. Finding one card won’t cause the fifth card to be included in the search.
4/18/2017 After the search is complete, the entire library is shuffled.