Sonic Mania strips away the more modern mechanics and features that have dominated the Sonic franchise and opts for a retro gameplay formula instead. As the robots attempt to bring the ruby back to Doctor Robotnik, Sonic, Tails, and their pal Knuckles give chase. By the time the pair reach Angel Island, the robots have already discovered the source of the energy, a crystal of immense power known as the Phantom Ruby. On the way, their trip is delayed by Doctor Robotnik's evil horde of robots, who attempt to stop their arrival. One day, Sonic and Tails hop on their plane to investigate a curious energy reading from the nearby Angel Island. Like in the early Genesis games, the story in Sonic Mania is straightforward and appropriately retro in nature.