In the fourth part of the famous series you have to lead fireboy and watergirl to the exit door in the ancient crystal temple.
In the third installment of the famous series, Fireboy and Watergirl are stuck in the Ice Temple. Similarly to the first game, you need to play together and find the way out in each level.
The first game of the famous series takes place in the forest temple. Control both, Fireboy and Watergirl, work together to reach the exit door, note that watergirl can't step on hot lava and fireboy can't step on water.