At one of the school's trash incinerators, Kanade and Otonashi meet up to talk about their plan. Otonashi decides to make Yui disappear first, but Kanade is not familiar with her. After some describing, Otonashi asks Kanade about her share, and she shows him the latest version of her Hand Sonic: a pincer-like weapon attached to her arm like a gauntlet. Otonashi describes the new version as "demonic" compared to her angelic nature.
With that, Otonashi explains to Kanade his plan, which involves her criticizing Yui's playing and taking her guitar, bumping at Otonashi and leaving Yui with Otonashi.
Meanwhile, at Girls Dead Monster's practice session, Yui is clearly seen struggling to fill in Iwasawa's shoes. Kanade soon appears, startling everyone, and, according to plan, tells Yui that her guitar is ruining the band. The other members are surprised about her ability to notice the flaw of their band and leaves Yui frozen in shock as she runs away with her guitar.
When Otonashi meets up with Kanade, he notices that she wasn't pursued. Otonashi decides to sneak up on the practice and notices that the band is improving without Yui's guitar. Hisako admits that Yui is right about having a rhythm guitarist is better, but she prefers another guitarist. Yui fumes at her remark and promises to get her guitar back, running away to chase after Kanade. The plan goes into motion again, with Kanade faking a collision with Otonashi, he gets the guitar and gives it to Yui, who is happy to have her guitar back, but is also pissed at Kanade.
Soon, Otonashi offers her a drink and they talk outside. There, Yui admits that she wants to do more than others. Also, she begins to recollect on her past.
Yui tells Otonashi that she was hit from behind by a car and was left paralyzed and bedridden, constantly relying on her mother to take care of her. Also her inspiration to play the guitar came from the music programs that she watches to pass the time.
Soon, Otonashi hears out the things that she wanted to do; she mentions hitting a homerun on baseball and playing soccer and professional wrestling. At first, Otonashi is daunted by how much stuff Yui mentioned, but he also realizes that most of the things she wanted to do is found on television.
Otonashi decides to help her first at professional wrestling. Yui tells him that she always wanted to try doing a German suplex to a person; that remark shocked Otonashi, since she added a tone of admiration to it, but he agreed nonetheless. Yui had difficulty at the start because of the height difference between the two, but he notices that she managed to carry him off his feet. However, she only managed to throw Otonashi back, giving him a nasty headache.
The two move to a different location - a more grassy one - to avoid Otonashi to receive more painful injuries. After a few tries, Otonashi discovers that Yui has a problem that's why she's failing: she can't arch back her body properly. With a few hours to teach her in making a perfect bridge, Yui tries one more time and succeeds. As she gloats on her triumph, Otonashi stays lying down, his back sore from being practiced on by Yui.
After a short break, Otonashi tells her that soccer is next; Yui then tells him that she wants a 5-on-1 match. With that, Otonashi tries to look for people to fill in. He manages to get Hinata, TK, Fujimaki and Noda to help him, lured by a letter "written by Kanade herself". Upon their discovery of Yui in the soccer field, their interest plummeted at first despite Otonashi's determination. But soon, they decide to jump in.
Yui storms through the team (with Otonashi's help) and some dirty tactics. With that, Noda and Fujimaki complain about the "spirit of sportsmanship" stated in the letter as TK gets shoved aside by Otonashi. Yui then finally faces Hinata, who acts as the enemy goalkeeper. She delivers a powerful kick to the ball and as Hinata braces for the impact, someone from a distance shoots at the ball, making it shift directions and making a goal. It was in fact Kanade, who used her Hand Sonic Version 5 as a slingshot to divert the direction of the ball. With that, Yui dances in victory while the others march back in defeat.
Yui and Otonashi proceed for the baseball field after the game. She set her target to be the zone beyond the safety nets at the end of the field, and after seeing Yui hit a handful of balls, he notices that it would take long until she nails her goal. After noticing that her grip is loosening up, he calls it quits and he plans to continue the next day.
The next day, there is still no progress. Otonashi is forced to call the day off and as Yui leaves the field, Hinata checks up on them and asks him what he is doing, picking up Yui's baseball bat. Otonashi did not answer, but responds with a question about having nostalgia in hitting a baseball. Hinata answers with a full swing which flung the ball far out across the field.
The day after that, Yui gives up after failing to hit another pitch. Otonashi checks up on her condition and he notices her fingers wrapped in bandages. Yui tells him that it is impossible and she is contented at what she has reached that time.
Soon, Yui tells him that she has one last wish: to be married. She admits that she can't do anything and God was cruel in taking all the happiness in her life. Otonashi disagrees, but Yui responds with a question: "Will you marry me then, senpai?"
Otonashi does not answer, but someone else answers: Hinata.Yui tries to dismiss his intent to marry her, telling that she can't do anything because she can't move, but Hinata tells her that he does not care about her handicaps. He tells her that wherever she is, even though she can't move, he will be on her side. He tells her how they would meet, saying that he would accidentally bat a ball through her window, and how afterwards, he would come by to talk to her every day. He tells her how, "before I know it, I'll be visiting you every day." He repeats the fact that no matter what condition she was in, he would find her, fall in love with her, and marry her.
With a sigh of happiness, Yui disappears.
The usual credits have been redone with a collage of images for when Hinata and Yui meet in the next life. After the credits, Hinata and Otonashi are standing alone in the baseball field and Yui's helmet and bat are left on the ground. Hinata turns to Otonashi, saying he will help Otonashi fulfill his plans.
Later, Noda and Ooyama are shown in a hallway with the look of fear and surprise on their faces as the former kills a mysterious shadow-like being."Wh...What the Hell did I just killed?" Noda said, eyes widening.
In a call from Yusa to Yuri, there is talk of a mysterious "Shadow" that Noda had just dispatched, that could have otherwise been dangerous.
- In the scene where Yui was watching TV (when she was still bedridden). There are stuff toys beside her that makes a cameo appearances in the series. The white giraffe and the dog stuff toy were referenced in the visual novel Air, developed by Key. The brown pig stuff toy was referenced in Clannad, another visual novel developed by Key.
- The title to the episode "Goodbye Days" may be a reference to the song Goodbye Days, by a Japanese singer, with the stage name, Yui.
Jun Maeda: I really want to thank director Kishi for putting Yui and Hinata together in the ED (in earlier episodes). Even I personally thought it was a little too sudden for Hinata to confess his love to Yui suddenly in episode 10, but the ED managed to help foreshadow this.
Seiji Kishi: After knowing their relationship in the main story, I wanted the ED to look like that.
Jun Maeda: Yui doesn’t get to speak much in the main story, so a large part of this was saved by the presentation. Also, episode 10 is personally where it’ll decide victory or defeat for me. If this episode doesn’t work, then it means I wasn’t able to live up to viewer’s expectations that they want to see a story that will make them cry, so I really want to know what people think of this episode when it airs. (from blog)