Spring, a Date, and Playing a Little Sister

Spring, a Date, and Playing a Little Sister (春とデートと妹ごっこ) is a Drama CD released on January 6, 2012. The story takes place between the events of Pentagon++ and Nise Random. This Drama CD marks the debut of Uwa Chihiro and Enjouji Shino's voice actors.

Summary
On an otherwise normal day, the five original members ("Pentagon")  of the Student Cultural Society come across a bizarre note. On the note, the names of the five second years, a few stars, and a message saying "You must grant the wishes of Uwa Chihiro and Enjouji Shino otherwise bad things will happen." The "Pentagon" suspects that the note was probably a message from No. 2 since the same thing happened before. Shino and Chihiro entered the club room and the second years were surprised and over-reacted. Inaba called all the seconds years to the hallways for a private meeting. At that time, they remembered Shino mentioning something about wanting to eat parfait. Aoki denied that could be a wish and suddenly had a stomach ache and rushed to the washroom. The remaining members realized that getting sick could be consequence for disobeying and that knowing No.2's past actions, they decided to grant the wishes of Chihiro and Shino. The second years decided to treat the first years to parfait and suddenly Aoki returned with his stomach ache gone. Knowing that this can not be a coincidence, the "Pentagon" invited Chihiro and Shino for parfait at a family restaurant while keeping the content of their conversation a secret. At the family restaurant, the StuCS ended up eating parfait together and fooled around a bit with Aoki asking for Yui to feed him. Yui tricked Aoki and ate the entire parfait quickly. Shino then said that feeding each other seem like a thing couples would do and Nagase added unnecessary comments which led to Shino asking to see what Taichi's and Inaba's dates were like. Knowing they must grant the wish, Taichi and Inaba decided to go on a date and let Shino and Chihiro follow to observe. During the Golden Week holiday, the StuCS met up. Taichi and Inaba were uneasy and embarrassed about letting others see their date but seeing that there was no other choice they decided to do it for the peace and calm of the StuCS. Taichi and Inaba had a brief argument on where to go first, either the Electronics shopping area or Pro-wrestling match first. They ended up going to the electronics shopping area first because Taichi said "Inaba is important to me so I go to where Inaba wants to first." Inaba reaction to that was what Nagase called "Dereban". While they were in the shopping district, suggestions by Nagase, Yui, and Aoki led Shino asking to see Taichi and Inaba hold hands. They did hold hands but were embarrassed about it. Later they went pass a cos-play shop which was having a contest to dress up as a character where the winner will get 15000￥. Shino saying that Nagase should do it and Inaba giving a push to Nagase telling her that she can't refuse, Nagase entered the contest and dressed up as a Mahou-shoujo (magical girl). They later went to a parfait shop and Shino wanted to see Inaba feed Taichi parfait. Embarrassed a bit angry at the others who were making suggestions she went on with feeding Taichi. But instead she was very violent in the feeding and missed Taichi's mouth and hit him in the face and knocked him over. Inaba started crying and thought Taichi was going to die but it was just an over reaction. At sunset, the group went to watch Pro-wrestling. The opening act involved an audience member to fight a "stupid wrestler" for entertainment. Shino and Chihiro wanted to see Yui being cool so Yui having no choice entered ring and performed some karate moves. Shino admired Yui's strength as a girl and the seconds secretly talked about Yui finally overcoming her Androphobia. After finishing the show, they coincidentally encountered Fujishima on her jog. Fujishima still a bit depressed about losing the election for Class president noticed that Taichi is always surrounded with girls and getting along with them well. She then remembered Watase's observation that Taichi might have a harem which made Shino and Chihiro interested to see what if Taichi went on a date with Yui and Nagase. Aoki and Inaba were shocked but knowing that this is a phenomenon they had no choice. On the next day, they met up again. Yui was wearing something different from usual which Taichi noticed. They only walked around and talked but Inaba and Aoki were following from behind enraged. They encountered Gotou and Fujishima again and they confirmed that Taichi does actually have a harem. After Gotou left in shock and anger not before telling Taichi that he'll take off 30 points off his test, the group continued their way home. On their way Nagase asked Shino that she likes Taichi's voice which suggested to Shino making her next wish. She wishes for someone with Taichi's voice to confess to her. Because of the phenomenon, Taichi had no choice but to think of a way to confess to Shino while Inaba was angry once again. On the next day, Taichi called Shino to a shrine near the school and said there was something important to talk about. Shino nervous waited for Taichi to speak. Taichi confessed to Shino saying "I love you, be my little sister." Shino shocked and extremely happy was speechless and then started stumbling on her own words. Taichi told Shino that she doesn't need to use polite language and call him "onii-chan". Shino embarrassed but still called Taichi "onii-chan". Taichi extremely happy as well collapsed and was also speechless and said, "my own little sister is number one in the world, you can be number 2" After too much embarrassment, they decided to call each other normally. The two went on a date but Shino noticed a group of suspicious people wearing sunglasses and masks were following them. One of the suspicious people went right up to Shino enraged but not before the others apologized and dragged that person away. Shino noticed that their voice was really familiar. The suspicious people gathered without Taichi and Shino knowing and turned out to be the rest of the members of the StuCS. Inaba could not stand Taichi being with Shino over-reacted but was stopped by the rest.

Cast

 * Mizushima, Takahiro as Yaegashi Taichi
 * Toyosaki, Aki as Nagase Iori
 * Sawashiro, Miyuki as Inaba Himeko
 * Kanemoto, Hisako as  Kiriyama Yui
 * Terashima, Takuma as Aoki Yoshifumi
 * Tōyama, Nao as Enjouji Shino
 * Toyonaga, Toshiyuki as Uwa Chihiro