The protagonist of the game is a muscular, loin-cloth wearing, Tarzan-esque tribesman named Toki, who up until recently lived a primitive yet contented life in the jungles of a vast and wild island in the South Seas.
This all ends tragically when the beautiful Miho, princess of Toki's tribe of jungle men, and a potential suitor to Toki, is kidnapped by the treacherous witch doctor Vookimedlo. Miho is taken to a vast golden palace at the summit of the island, which Vookimedlo has conjured up for himself to reside in. The wicked shaman then casts a spell to transform all the human inhabitants of the island into various animals and beasts, before they can defend themselves against the evil magic.
Toki himself is transformed into a Geeshergam; one of the ape-like minions of Vookimedlo; although in his primate form Toki more resembles a gorilla. Fortunately the great warrior discovers that he is still in control of his own faculties and as an unexpected side effect of the spell cast on him, he can breathe fire and shoot forth various projectiles from his mouth.
Toki then sets off on a quest to pursue and defeat Vookimeldo, rescue princess Miho, and undo the curse which has befallen the island. However, to reach Vookimedlo's golden palace, Toki will have to travel through murky lakes, steep canyons, over frozen ice-capped mountain ranges and lava-spewing volcanoes alike. To progress in his quest and be ultimately victorious, Toki will have to battle all manner of dangerous wild animals and various mutants of Vookimedlo's creation; not to mention Vookimedlo's own abominable guardians who act as level bosses.
Source: Wikipedia, "Toki," available under the CC-BY-SA License.