The Mystery Tales Title is Tales of the Heroes Twin Brave
Action oriented Tales spinoff.
Namco Bandai's announcement of Tales of Innocence R for Play Station Vita earlier today came with notice that another Tales game is in the works. Weekly Shounen Jump reveals the mystery title to be "Tales of the Heroes Twin Brave."
Twin Brave is an action offshoot featuring characters from a number of Tales games. Players face off against foes as a party of two.
Tales of the Heroes will be formally announced at Namco Bandai's Tokyo Game Show Tales of series briefing on the first day of the show. Expect more details shortly.
Correction: This story previously wrote that the game is for PlayStation Vita. The current information leaking out of Jump indicates that the platform is actually PSP. We should have confirmation in a few hours.