Sonic CD is a Sega CD game set on the distant Never Lake's Little Planet, renowned for its unique convergence of past, present, and future through hidden Time Stones. Sonic discovers this once pristine world trapped under a menacing metallic shell, the nefarious work of his long-time adversary, Dr. Eggman, aimed at seizing control over time using the Time Stones. Throughout the game, Sonic embarks on a time-traveling journey using Little Planet's power to dismantle Dr. Eggman's machinations in history and retrieve the lost Time Stones, thus thwarting his evil plans.
Sonic travels to the distant shores of Never Lake for the once-a-year appearance of Little Planet - a mysterious world where past, present, and future collide through the power of the Time Stones that lie hidden within it.
Sonic arrives only to find the once beautiful world imprisoned beneath a twisted metallic shell. His arch-nemesis, Dr. Eggman, has come for the Time Stones and with them, will soon have the power to control time itself!
In order to put an end to Dr. Eggman’s nefarious schemes, Sonic must use the power of Little Planet to travel through time; breaking Dr. Eggman’s hold over the future by destroying his machines in the past and recovering the missing Time Stones!