You need to find a key to open the chest that cointain the gem that will reorganize the proper functioning of the seasons without your power. If you want a better score, you can just collect the coins hided on all the map.

In 4SA, everything is affected by the seasons.
For example, during the winter, the water is becoming ice, so you can walk on it. In summer, it’s drying up, so you discover new areas.