Complex sentence: The two attempt to fix their ruined future world by traveling back in time and then again, as main character in "Sonic Rush Adventure", where Sonic and Tails are transported to her dimension and help her retrieve the "Jeweled Scepter".
Split into simpler sentences: The two attempt to fix their ruined future world by traveling back in time. She appeared again as the main character in "Sonic Rush Adventure", where Sonic and Tails are transported to her dimension and help her retrieve the "Jeweled Scepter".