The Nightly Challenge is a special level you can play each evening and win a prize.
You can access the Challenge on the Map screen by pressing the round golden button. The level is playable each evening from 18:00 until 00:00. The button is visible only during this time window.
It can be played multiple times until it's completed. Playing the Nightly Challenge does not cost Energy. When the level is won, the Nightly Challenge can be played again the next evening.
The basic structure of the level is always the same, but the quests are randomized.
The prize for winning the Nightly Challenge is 1 Diamond, 50 Gold, and a Token if you achieve all 3 stars!