One day, a gifted graduate student in Saitama University's science department, Himuro Ayame, confesses her feelings to Yukimura Shinya. However, as neither of them have any experience with romance, they are worried as to whether it truly is love or not. They decide to discover "the standard conditions of love" so that they can judge each other's feelings by them. Even as their underclassman in the lab, Kanade, throws up her hands in exasperation, Yukimura and Himuro attempt to quantitatively measure "thrilling palpitations of love" by taking their heart rates while performing actions such as "kabedon," "chin-lift," and "sleeve-roll," but...

To find proof as to whether he is "in love" or not, Yukimura pats Himuro on the head from point-blank range. Seeing this, Ibarada, an upperclassman in the Ikeda Lab, talks about the need for a control experiment. In other words, in order to prove that the racing of his heart is because of Himuro specifically and not just because he's facing a woman, Yukimura has to pat Kanade and Ibarada on the head too. Himuro, on the other hand, sets out to prove that food made with love tastes better and cooks, but...

When Himuro finds out that her junior in the Ikeda lab, Kosuke, has spent over 220 thousand yen on his beloved Aika and holds her every night when he goes to sleep, she is shaken by the realization that the only present she's ever given Yukimura is a notebook, and that she's never held him while she slept. She worries that she can't objectively call what she feels "love." As Yukimura and Himuro endlessly debate "love" using numbers, Kanade proposes that the two of them go on a date, but...

Yukimura and Himuro wear lab coats, as befits science-types, as they get ready to begin their date experiment. Kanade is there to watch over their date and record observations, but she can't help bursting in to tell them to buy date clothes. Both of them are wearing monitors for heart rate, blood pressure, and temperature, and they're using an app to record things like "times my heart raced," "times I felt happy," "times I felt relaxed," and "times I felt uneasy." Suddenly, a man appears and starts hitting on Himuro...!?

Today is a day when the members of the Ikeda lab gather to announce research results. When Kosuke cites Aika as an excuse for not having read the papers he was supposed to, Professor Ikeda's muscles expand and he crushes a pen to smithereens. On the other hand, Yukimura and Himuro give a joint presentation of the results from the date they went on. As they present the records stating in which situation their highest recorded heart rates were, writhing in distress with the embarrassment, Professor Ikeda's reaction is... On top of this, In order to increase the amount of experimental data, Yukimura and Kosuke, and Ibarada and Kosuke, form pairs to measure data on their vitals...

Ibarada suggests that one of the greatest factors in the base conditions of romantic love is "whether or not you want to kiss the person," so Yukimura decides to try to kiss Himuro. However, Himuro doesn't like the idea of a kiss where the exact angle is measured with a protractor. When Himuro realizes that if the mood were more like it had been in the Ferris wheel, she might not mind a kiss, she and Yukimura create an equation to numerically define "mood value." In what location might the "mood value" be highest? And will the two of them be able to kiss...?!

The first semester has come to a close, and the Ikeda lab is having a party where everyone's bringing what they like to eat and drink. They're having fun, playing games like the "prime number Yamanote line game," when a drunken Himruo finally does a certain something with Yukimura... And even Kanade ends up drunk... On the other hand, the mood quantifier obtained through the previous round-robin kiss experiment has progressed their research tremendously, and in order to gather more data, Yukimura and the others use fairy tales such as "Snow White," "Kaguya-hime," and "The Crane Returns a Favor" as references, but...

Yukimura and the others will be giving presentations at the summer study sessions. There's less than a month left until the training camp, but Kosuke still hasn't picked a research theme. Professor Ikeda suggests research into "an algorithm that could instantly find the True End in any dating game." On the other hand, Yukimura and Himuro are focused on the hormone which is released when a person is touched by someone they love - oxytocin. By investigating the amount present in a person's saliva, they think they might be able to determine if the person loves the one who touched them, and they decide to immediately put it to the test with some close contact...

At long last, it's the first day of the summer training camp. On the plane, Yukimura presses close to Himuro and tries to collect her saliva in spite of the surrounding gazes. Manga artist Yamamoto observes them with an eerie smile. On the beach in Okinawa, the midsummer sun shines down on Yukimura and Himuro in their swimsuits, and they immediately attempt to begin their close physical contact experiment. However, since they're doing it, they choose to seek "the position which offers two people having close physical contact the greatest contact area"...

As Himuro looks out over a sunset colored ocean from her room in the resort hotel, Yukimura barges in saying, "we have to do now what we couldn't do this afternoon." The next day, it's finally time to make their presentations in front of a huge audience. Kosuke boldly gives his presentation on romantic visual novel games, but one of the professors grills him, asking, "what purpose does this research serve?" On the other hand, when Kanade falls into a panicked state just before her presentation, Yukimura hugs her, not realizing that Himuro is watching.

Kanade finishes her presentation safely, but when she goes backstage, Yukimura and Himuro are fighting. Before her presentation, Yukimura hugged Kanade, trying to help calm her anxiety. Out of jealousy, because she hasn't been able to do any close contact experiments with Yukimura lately, Himuro ends up saying some very harsh things to Yukimura. In return, Yukimura finds himself replying, "it isn't as if we're dating, is it?" The heartbreaking statement causes Himuro to race from the room. Having witnessed this scene, Yamamoto smiles an eerie smile...

For some reason, the glasses case Himuro gives Yukimura as a present is smashed to pieces. Shock sends Himuro racing away from the scene. Ibarada points out that it could have broken when Himuro fell on the stairs, but Yukimura estimates the force of impact based on the case's mass, materials, and height of fall, and concludes that someone must have deliberately destroyed it. Finally, at dawn, Yukimura finds Himuro crouched alone, barefooted, on a bridge. Will they be able to reconcile? And will they be able to prove their love...?!

히무로와 유키무라는 이론적으로 최고의 키스를 했지만, 타액량 재측정을 위해 스이우와 그의 연인 크리스를 찾아간다. 둘은 ′좋아한다′의 증명에 대해 도움을 요청하고, 스이우 커플은 압도적인 사랑의 아우라를 보여 준다.

타액 측정을 위해 둘은 다시 한번 키스하지만 옥시토신양에서 스이우 커플에게 대패하고 만다. 초조해진 유키무라는 대조 실험을 제시하지만, 실험 중 스이우에게 유혹당하는 모습을 히무로에게 보이고 결국 말다툼을 한다.

이바라다는 이케다 교수에게 박사 과정 진학을 권유받지만 결정하지 못한다. 유키무라는 감기에 걸린 히무로의 병문안을 가고 열이 오른 모습에 두근거린다. 그때 카나데가 찾아오고 유키무라는 급히 이불 속으로 숨어버린다.

카나데는 ′연구실 이과 여자 모임′을 개최하고, 분위기를 고조시키기 위해 히무로에게 유키무라의 어디가 좋은지를 묻는다. 코스케는 아이카 성우의 라이브에서 팬라이트를 흔들며 즐기다가 이바라다와 히무로를 발견한다.

시키조의 고백을 받은 카나데가 예전 짝사랑의 기억 때문에 불안해하자 유키무라는 방정식으로 조언해 준다. 한편 야마모토가 그린 만화가 공개되고, 독자로부터 수집한 ′좋아한다′의 자료를 받게 된다.

히무로는 유키무라에게 좋아한다고 고백한다. 첫 번째 고백과는 다른 담담한 모습에 유키무라는 판정의 근거를 묻고, 히무로는 함께 한 실험을 떠올리며 마음을 전한다. 둘은 이 증명을 끝낼 수 있을까?

카나데는 고민 끝에 시키조와 데이트해 보기로 한다. 그러자 유키무라는 새롭게 고안한 호감도의 단위인 ′카나데 러브 파워′를 이번 데이트에서 계측한다고 단언하고, 단체 데이트를 제안한다.

코스케는 아이카와 데이트했지만 그건 데이트가 아닌 인형 놀이일 뿐이라는 자각에 절규한다. 카나데는 짝사랑의 기억을 고백하며 평범하지 않은 자신을 탓한다. 이를 듣던 유키무라는 평범함에 집착하는 카나데와 언쟁한다.

학교 축제에서 발표회를 준비하는 이케다 연구실. 유키무라는 연애에 있어 외모의 중요성에 대한 실험으로, 코스프레 의상을 빌려주고 매력도를 평가하는 방법을 제안한다. 연구실 멤버들은 축제에 대한 기대로 한껏 들뜬다.

유키무라에게 과외를 받는 여고생 하루는 사이타마 대학 축제에 놀러 가고, 잠깐 한눈팔던 중 경찰 복장을 한 히무로와 부딪힌다. 한편 유키무라는 매력도 평가를 위해 여장 코스프레를 하게 된다.

코스프레 의상으로 웨딩드레스를 입은 이바라다는 얼떨결에 코스케와 사랑의 서약을 한다. 시키조와 축제를 구경하던 카나데는 유키무라와 마주치자 차갑게 돌아선다. 그날 밤 시키조는 카나데에게 사귀자고 고백한다.

카나데가 고백을 거절하자, 분노한 시키조는 카나데를 기절시키고 만다. 어두운 폐창고에서 눈을 뜬 카나데의 앞에는 불량배들이 있었고, 위기의 순간 위험을 눈치챈 유키무라가 카나데를 찾아낸다.