Sonic Underground

Queen Aleena Hedgehog tells the story of how Dr. Robotnik took over planet Mobius and how she had to give up her three children Sonic, Sonia, and Manic to fulfill a prophecy that one day the siblings will be able to rise against Robotnik's rule and restore peace to the planet.

Argus, is captured by Sleet and Dingo before he can reach the secret rendezvous where he was to meet Queen Aleena.

A homecoming is interrupted for Sonic, Sonia and Manic when Sleet and Dingo arrive to collect back taxes after returning to their birthplace.

Sonia discovers that the watch she received from her friend is actually a monitoring device for the Robotnik Intelligence Agency.

Sleet and Dingo make a plan to collect the taxes due to Robotnik but they intend to keep it for themselves.

Robotnik blackmails Cyrus by kidnapping his father and holding him hostage.