Sega quietly began a new spinoff franchise with Sonic and the Secret Rings. The first Sonic Wii game put Sega's mascot into an Arabian Nights-influenced world. The followup, Sonic and the Black Knight, was announced as the second entry in the "Storybook Series."
New North American boxart for Black Knight found on Amazon shows that Sega has now decided to officially identify the game (and thus Secret Rings, retroactively) as a Storybook Series entry, right there in the corner of the label. And, really, the only reason to do that now is to set it up as an ongoing series. That means more Wii Sonic games in different worlds taken from classic stories. Hopefully for Sega, this initiative will work out better than Nintendo's Education Series.