You will need lockpicks to open other dungeons in multiplayer and single player modes.

Here is how to get them:

1. Just wait
Lockpicks will replenish over time. To speed up this process, increase the Lock Pick Speed restoration in the upgrade menu (tap on the castle icon in your dungeon or simply swap down).

2. Watch ads
If you run out of lockpicks while trying to break into a dungeon, the game will prompt you to watch an ad to get additional lockpicks. Note that you can only watch a limited number of ads, otherwise this feature would have been overpowered. They will start showing again after some time.

3. Make a flawless raid
Reach the totem without a single death to replenish all lockpicks. Note that lockpicks earned by watching ads and purchased with orbs will not be restored.
4. Spend orbs
You can also restore all lockpicks for orbs if you run on empty while trying to get into a dungeon.
5. Buy a Special Offer
There is also a limited time offer with lockpicks that can appear in the shop while playing the game.