Uta no Prince-sama All Star After Secret first launched for PSP on March 12, 2015.
Here is an overview of the game, via VNDB:
This game will focus on the four senior idols. Combining those four with the seven junior idols from the original series, there will be a total 11 idols with routes! The game is split into two main grand routes; the “Quartet Route,” featuring the four seniors, and the “Rainbow Route,” featuring the seven juniors. Both grand routes are then further divided into the individual idols’ routes.
The story of the Quartet Route takes place after the events of Uta no Prince-sama All Star. It begins with Nanami Haruka and her chosen partner already as lovers. What is in the future that awaits Haruka and her beloved?
This will be a story about the seven juniors, who are now all fully-fledged idols. Like the Quartet Route, the story begins with Haruka and her chosen partner already as lovers. Here, you’ll be able to read stories about her sparkling, happy days spent with her boyfriend, who’s now shining as an idol.