Search target opponent's library for a card and exile it face down. Then that player shuffles. You may look at and play that card for as long as it remains exiled.
Other players, including the card’s owner, can’t look at the card while it remains exiled.
Playing a card exiled with Praetor’s Grasp follows all the normal rules for playing that card. You must pay its costs, and you must follow all timing restrictions, for example.