In a safe place.

If you have something you don't want to lose, you might put it in a safe place. Sometimes, however, you put it in such a 'safe place' that later you can't find it.

Example:
-Do you have the tickets for tonight?
-I put them in a safe place and now I can't find them.

Between a rock and a hard place

If you're 'between a rock and a hard place,' it means you're in a difficult situation with no good way out. No matter what you decide to do, there will be negative consequences to your actions.

Example:
-I can buy groceries and pay my bills this month, or I can refill my prescriptions.
-You're definitely between a rock and a hard place.