Three successful challenges in The Return mission will provide you with a new loading screen. On this illustration we can see on the small pier the location of the hidden star. No doubt about it: this week it is located on the bank of Fatal Fields pond!
Map
All you have to do is land on the small wooden pier in the southern part of Fatal Fields, near the small lake. Once again, the Team Rumble mode will give you all the time you need to find the star without making an unfortunate encounter. At the end of the bridge you will find the hidden star.