Perhaps you are thinking of one of these:
* Sonic Frontiers: This is the most recent Sonic game, released in 2022, and could be considered the "latest story".
* Sonic Mania: This is a retro-inspired game released in 2017 that takes inspiration from classic Sonic games, but isn't directly a part of the main storyline.
* Sonic the Hedgehog (2006): This game had a complex storyline, but was heavily criticized at the time.
Please clarify which game you are referring to, and I can give you more information about its release date and availability.