Big's Fishing Derby is a total-conversion modification of Sonic the Hedgehog 2, based on Big's Fishing mini game in Sonic Adventure, the same premise applies.
Big must catch froggy to obtain the emerald he swallowed, Dr. Robotnik also is fishing for froggy to obtain all the Chaos emeralds!
Big must protect froggy and keep the emeralds out of Robotnik's hands!
