Rescue Rush is a game mode in which you'll need to answer questions correctly in order to save the game's characters. As soon as you enter you'll find different challenges, in which you'll be required to answer a certain number of questions in order to move on to the next challenge (save the character) and so on until you complete every objective.
You'll have a set amount of time to complete each challenge; you'll gain additional seconds for evey question you answer correctly. If you answer incorrectly, seconds will be deducted. If you don't know the answer to a question, you'll have the chance to pass on to another question.
If you run out of time to answer, you'll be able to renew your attempts by using tickets or by watching promotional videos. At the top of the screen you'll be able to see the number of tickets you have, as well as the time you have left to complete this mode.
Every time you complete a challenge, you'll get crowns and, if you complete every challenge, you'll get gold bars as an extra prize.
You'll be able to access Rescue Rush by tapping on the "Events" button, which you'll find at the top right corner of your dashboard, under the "Missions" button.