Unyielding Gatekeeper

If you controlled the target permanent earlier in the turn but not at the time Unyielding Gatekeeper's last ability resolves, you won't return it to the battlefield tapped. The player who controlled that permanent at the time it was exiled will create a Detective.

The face-down spell has no mana cost and a mana value of 0. When you cast a face-down spell, put it on the stack face down so no other player knows what it is, and pay {3} to cast it. This is an alternative cost.

Any time you have priority, you may turn the face-down creature face up by revealing what its disguise cost is and paying that cost. This is a special action. It doesn't use the stack and can't be responded to. Only a face-down permanent can be turned face up this way; a face-down spell cannot.

Turning a permanent face up or face down doesn't change whether that permanent is tapped or untapped.

If a face-down creature loses its abilities, it can't be turned face up with a disguise ability because it will no longer have a disguise ability (or a disguise cost) once face up.

At any time, you can look at a face-down spell or permanent you control. You can't look at face-down permanents or spells you don't control unless an effect instructs or allows you to do so.