Lovely Complex

170 cm tall Koizumi Lisa and 156 cm short Ōtani Atsushi have been quarelling ever since they entered Maido Academy, to the point that their feud is compared to the Tigers-Giants rivalry. Lisa had falled for Suzuki Ryouji at first sight, Ōtani had a crush on Lisa's friend Tanaka Chiharu, so he arranges a merry triple date. However, they both get rejected because of their complexes about their tallness and shortness, respectively. In the end, Suzuki and Chiharu discover they have feelings for each other... On the other hand, Lisa and Ōtani discover that they essentially have the same complex and start a of who can get a partner first.

Lisa and Ōtani both love the singer Umibōzu. Since they managed to get tickets for the christmas concert, they make plans to go together. That's when Ōtani's ex-girlfriend Kanzaki Mayu hits him up with a request to meet her on christmas day. Cue a flustered Ōtani. Seeing Ōtani like that, Lisa graciously removes herself and decides to go to the concert alone. The day of the concert, Lisa is alone in a city overflowing with couples. The person that keeps flashing through her heart is Ōtani, who's always stuck around with her. When she's in the deepest pit of sadness, Ōtani runs up to Lisa. Saying that he needs prioritize the promise he's already made, he takes Lisa's hand and a warm affection courses through Lisa. But right then, a tall male figure suddenly appears and embraces Lisa!

The tall handsome guy who suddenly embraced Lisa was an old childhood friend of hers, Fukagawa Haruka. It's Valentine's Day. Lisa can't decide if she wants to give Ōtani chocolates. Ōtani dismissively says that he'd take politeness chocolates. While she puts on a defiant front, Lisa's actually happy. Haruka then makes his appearance and gets in a fight with his love rival, Ōtani. Ōtani comes to the irritating realization that Lisa and Haruka look good together just standing there, and even rejects Lisa's chocolate. That chocolate then ends up with Haruka. The next day, Lisa apologizes to Ōtani who's looking all depressed. They both quip that it was just politeness chocolate, and they end up getting a little closer.

It's the new spring semester, which means being a sophomore. The love rival Haruka ends up being in the class next door, and Lisa is relieved to be in the same class as Ōtani again. Ōtani is pouring all his energy into basketball, so Lisa buys wrist bands for him. Not being able to be honest about her feelings, she can only give him the present as an extension of their usual quarelling. Annoyed at herself, Lisa gets down because her unlikeable personality. That's when the cute Kotoboku Seiko, the polar opposite of Lisa, makes an appearance. Of all the things to do, she suddenly kisses Ōtani. Aghast, Lisa is cast down to the bottom of hell...

After Seiko stole a kiss from him, Ōtani is absolutely smitten. On top of that, Lisa has grown and is now 172 cm tall, widening the height difference to Ōtani even further. Then Ōtani sprains his finger during basketball practice and Seiko nurses him in the nurse's office. Being all alone in there, Seiko throws herself onto Ōtani. ...but then, Seiko is actually a boy named Seishirō. Seeing Seiko go all in for the person they love despite everything is a wake-up call for Lisa. Internally, she declares that she will stop denying her feelings and admit that she loves Ōtani.

Even though all her friends are helping Lisa confess her feelings, Ōtani is so dense in that regard that he doesn't get it. Even worse, Ōtani doubles down on his cluelessness and asks her who she likes so he can help with the confession. It's Lisa's birthday. Ōtani asks Lisa to come to the station skyrise. As his present, he secured two special seats just for them to watch the fireworks from there. That kind gesture deepens her feelings for him even more, and Lisa blurts out her confession. "...I... I love you Ōtani!"