What it does
Hideaway lets a permanent (usually a land) exile the top few cards of your library face down when it enters, and you secretly look at them and stash one away. Later, when a specific condition is met, you can play that exiled card—often for free or at reduced cost.
The big rules nuance: hideaway only sets aside the card; it doesn't let you play it. You still need the permanent's separate triggered ability to actually cast or play the hidden card, and you must satisfy that ability's condition. Also, modern hideaway (like the "Hideaway N" wording) typically lets you look at a set number, exile one, then put the rest on the bottom.
In Commander, hideaway lands like Windbrisk Heights or Shelldock Isle quietly bank a bomb for later. They reward going wide or filling your graveyard, giving repeatable card advantage and a free spell when conditions align—strong but slow, since you can't access the card immediately.













