According to official website, an un-aired episode of drama romance anime series, Amagami SS plus was announced and it will feature Junichi Tachibana’s sister, Miya.

The un-aired episode is titled “Olsen” or hot spring in English and it will be included in the seventh volume of the Blu-ray that is set to release on October 3, 2012.

Synopsis
In the episode, Junichi hasn’t gone around with any girls yet. Miya goes to a hot spring with Sae and Ai. There she meets Tsukasa, Rihoko, Kaoru and Haruka. The main characters except Junichi enjoy girls’ talk in the hot spring.

[Source]