Mei is the younger sister of Youhei. She is staying at her hometown of Honshu and worries constantly about her older brother.
Mei is a big fan of Yusuke's music. She also enjoys teasing Tomoya with her younger sister charm, calling him "onii-chan" (an endearing form of "older brother" in Japanese).
Youhei is well-known for his mischievous behavior. Mei would be bullied by the boys who disliked Youhei and Youhei would come to her rescue.
When Youhei moved out to attend high school, she was worried about his well-being.
On April 23rd, Mei phoned Youhei's dormitory to announce that she will be visiting him. Misae took the call but Youhei was in the shower. If Tomoya chose to talk to Mei, she will announce that she will be arriving that Saturday.
Sunohara Siblings' path
Mei met Tomoya at Youhei's dorm room. Tomoya assumed that Mei would be as loony as Youhei and was greatly surprised to find her to be very sensible. Tomoya explained that Youhei was on a date with his girlfriend and Mei was shocked to know that he has a girlfriend. Mei volunteered to cook dinner and requested Tomoya to clean Youhei's room. Mei requested to meet Youhei's girlfriend. Mei revealed that she has no place to spend the night and Tomoya offered to house her.
The following morning, Mei woke Tomoya up, cleaned his room, and made him breakfast. At noon, Tomoya and Mei went to the park and met Youhei and Sanae. Mei was in awe at how wonderful Sanae is and was shocked to see Youhei having such a nice girlfriend. Youhei invited Sanae to lunch near his dorm and revealed his poor diet. Sanae cooked lunch for them instead.
That evening, Youhei invited Sanae to town. There, they found a group of boys bullying a girl. Youhei wanted to ignore them but Sanae insisted on rescuing her and returning her to her parents. Mei was shocked and sad to see Youhei had changed for the worse. The next day, Tomoya confessed that Sanae was not his girlfriend.
The following day, Mei tried to talk to Youhei but he ignored her. Mei was frustrated by Youhei's behavior and she went to town with Tomoya. There, Mei bought one of Yusuke's music CD and they met Yusuke too. Yusuke noted that Tomoya had changed. Mei expressed her love for Yusuke's music but he insisted that he is no longer the artist that he once was. That night, Mei kissed Tomoya on his cheek to thank him and Youhei witnessed them. Tomoya pretended to be her boyfriend. Youhei became angry but he didn't respond.
On Wednesday, Mei met Tomoya after school. They agreed that Youhei should go back to playing soccer. Mei approached the soccer club coach and begged him to allow Youhei to play. He sent her to gain approval from the soccer club captain. The captain turned her down. At school, Tomoya requested Youhei to play soccer again. Youhei declined and Tomoya was frustrated by his apathy. Tomoya met Sanae at the park and requested her to focus Youhei's attention back to Mei. Sanae assured him that Youhei had always been thinking of Mei.
Tomoya and Mei approached the soccer club captain again. Mei volunteered to fetch soccer balls for them during practice. The players purposely made her job difficult. After sundown, the captain still refused to accept Youhei and bullies her. Youhei then appeared and he and Tomoya fought againt the soccer club members. They were beaten up. Later, Tomoya yelled at Youhei for not protecting Mei but Youhei yelled that he was fine with Tomoya being Mei's boyfriend. Youhei then yelled at Tomoya for putting Mei through such difficulty.
The next day, Tomoya and Youhei made up and became friends again. Mei was happy to see Youhei enjoying his school life and returned home.
On April 26th, Tomoya and Nagisa met Mei outside Youhei's dormitory. Tomoya wanted to run away but Nagisa introduced themselves as Youhei's friends. Mei and Nagisa introduced themselves to Misae and Tomoya brought them to Youhei's room. They cleaned Youhei's room. Tomoya revealed to Mei that Youhei had quit the soccer club. Nagisa revealed that Tomoya and Youhei were preparing for a basketball game. Mei revealed that she has no place to stay and Nagisa offered to house her.
The next day, Tomoya visited the Furukawa bakery. Mei revealed that she and Nagisa had stayed up the whole night talking about Tomoya. Mei tasted one of Sanae's bread and it was bad. Nagisa volunteered to run the shop with Tomoya and Mei and they made a great sale. The next day, Mei taught Nagisa to be more expressive and Tomoya was surprised by Nagisa's new-found confidence. The following day, Mei bade the Furukawa family goodbye and returned home.