Ardy Lightfoot is an anthropomorphic creature resembling a fox or cat. He is accompanied by his best friend Pec, a blue penguin. Pec can be used as a weapon, or can take the role of various other helpful devices like a hot air balloon or rock destroyer. If Ardy is hit by an enemy, Pec disappears, and can be retrieved back from a chest. If Ardy is without Pec, he can still attack by bouncing on his tail. He can also protect himself temporarily by hiding behind a mirror.

The story of the game is that the sacred rainbow has shattered into seven pieces and it's up to Ardy to obtain them all again. Whoever collects all seven pieces will receive one wish. An evil king named Visconti has already gotten one piece and is searching for the others. To this end he sends out various creatures and henchmen such as Beecroft, Catry and others. These creatures form the opponents for Ardy during the game. Ardy is assisted by friends along the way like the elder (unknown name), Nina, and a mysterious adventurer named Don Jacoby.

When Titus published Ardy Lightfoot for North American audiences, several changes were introduced. These included numerous sprites, such as Ardy's "waiting" pose, being removed; tied up and crying animals being removed from the background on the forest level; and in level 6, "Eaten!", Catry's gruesome death by acid was written out of the plot; instead of being reduced to a pile of bones, she is merely knocked unconscious.