Middle school graduate Rentarou Aijou is in a funk over his latest romantic confession being rejected. He explains to Anonymous Friend "A" that this is his 100th rejection, with his desire for a girlfriend going all the way back to when he was 8 months old. While disturbed at how early a bloomer Rentarou is, his friend is still baffled that he could confess to 100 girls and not have a single one of them reciprocate his feelings. The two part ways with Rentarou being assured that his rejection streak is bound to grow leaps and bounds through high school.
Later, Rentarou visits a shrine and prays that he get a girlfriend, whereupon the God of Love emerges and informs Rentarou that he will get his wish. Although initially skeptical of the deity and his promise, Rentarou quickly learns that he is destined to meet and fall in love with 100 girls during his high school career.
Fast forward to Rentarou's first day of high school, and he crashes into two girls walking in the hall. Looking them in the eyes triggers a sudden ZING!!, the telltale sign of meeting one's soulmate. As they recover from the sensation, Rentarou tries to help the girls up, with one of them flirtatiously acting like she hurt her leg and the other flusteredly mimicking the former. Rentarou buys the charade and beats himself up for hurting his first two soulmates before escorting the girls to the nurse's office. On the way there, the two girls, Hakari Hanazono and Karane Inda, overhear two other girls discussing a rumor about pink four-leaf clovers and how they supposedly guarantee an accepted confession, prompting them to run off in search of one from the school garden.
Four hours after school lets out for first years, Rentarou has finished helping a teacher search for a missing pair of contact lenses and spots Hakari and Karane searching the school garden for pink four-leaf clovers. Hoping to get into their good graces, Rentarou buys two cans of juice for the girls, with Karane fighting up gratitude and Hakari attempting to get an Indirect Kiss through the can but failing. As Rentarou tries to help Hakari clean up the mess made as a result, she immediately confesses to Rentarou. Karane then shows up, having wanted to give Rentarou something in return for the juice, but didn't know what flavor he preferred and ended up buying every single kind. After chastising Hakari for upstaging her, Karane also confesses to Rentarou.
Unable to decide which confession to accept, Rentarou returns to the shrine to ask the God of Love for advice. He explains that since they're both his soulmates, he'll never be able to choose one over the other. While most people are supposed to have one soulmate in their life, the God of Love accidentally racked up Rentarou's soulmate count by two figures while watching Castle in the Sky. Furthermore, if Rentarou doesn't reciprocate the feelings of a soulmate, she'll die. With this in mind, Rentarou considers secretly two-timing both girls to ensure neither of them feels rejected.
However, he quickly beats himself up for considering such an idea, and so he decides to accept both confessions simultaneously, presenting each girl with a pink four-leaf clover. Karane is skeptical that he can possibly be sincere, but Hakari is quickly charmed by his sincerity. Despite this, the girls both decide that he does mean well and agree to both date Rentarou simultaneously.
However, this is only the beginning, and Rentarou still has 98 more girlfriends to meet.
Rentarou is so excited that he finally has a girlfriend that he talks about it to a telephone pole. Hakari and Karane show up, and the trio walk to school hand-in-hand while talking about the weather. Along the way, they start calling one another by their first names with and without honorifics. When they get to school, the vice principal chases down a student running in the halls and gives him a deep kiss. While explaining her reputation to Rentarou, Hakari and Karane discover that he's never kissed a girl before, which means whoever kisses him first will get Rentarou's First Kiss.
The group gathers on the roof during lunch, and Hakari and Karane take turns feeding Rentarou with bites from their bento and homemade cookies respectively. Hakari plays the bocky game with Rentarou, prompting Karane to try and play as well. Things escalate quickly as a wayward sneeze leads the girls to pretend he's sick as an excuse to kiss him. Rentarou catches on that they're both trying to get his First Kiss and, after calming the girls, explains that he created a game that would allow him to kiss both girls without anyone knowing who was kissed first. The game involves blindfolds, music through earbuds, and dice rolls, in order to randomize the order in which the girls were kissed. Hakari is immediately sold on the idea, but Karane points out that Rentarou could easily cheat without the girls' knowledge. As such, Rentarou implements a "failsafe" by having all three of them Pinky Swear not to cheat.
It doesn't take long for the game to spiral out of control, however, as the players repeatedly suffer embarrassing screwups. Eventually, all three of them decide the game is more trouble than it's worth, and Rentarou decides the sanest option would be to invoke the wrath of the vice principal. But when he leaves and the vice principal catches him, the girls wrestle and scare her away, explaining that he should let the other girl kiss him first instead. But that still leaves them back at square one, so Rentarou proposes a three-way kiss. (It was actually his first idea, but he rejected it since it would mean the girls would kiss each other in the process.) Having suffered enough embarrassment from the convoluted kissing game, the girls agree to the three-way kiss.
Rentarou and the girls visit the school library, with Hakari wanting to find some new recipes with which to entice Rentarou. Karane tries to get ahead of Hakari on that front and search for recipe books herself. While the two squabble over books, Rentarou goes to find his own books.
He begins browsing the romance section, where he notices a hand struggling to reach a high shelf. His eyes meet the face of the hand's owner and—ZING!!, another Love Shock. After recovering, the girl opens a book and points out a passage inside. After reading the indicated excerpt, Rentarou notices her armband and realizes she's part of the library staff, which the girl affirms with another book excerpt. Thinking she's using the book to talk because they're in the library, Rentarou tries to use sign language to tell her what he's looking for, to the girl's confusion.
Apologizing for a sudden outburst, Rentarou tells her what he wants to read, and the girl rounds up a heavy selection of books. Rentarou tries to borrow all the books she collected, but another library staff member tells him he needs a library card first and will have to wait a week before he can get one. As such, the quiet girl lends him her own book before introducing herself as Shizuka Yoshimoto.
That night, after reading the book, Rentarou mulls over the fact that he now has three girlfriends.
Meeting up with Shizuka the next day, she lends him the next book in the series before Rentarou buys her a drink as thanks for lending him the first book. While out in the courtyard, Rentarou finally understands Shizuka's pointing out book excerpts to be her method of communication. Upon learning of her implied self-esteem issues, Rentarou asks to borrow the first book again.
Three days later, Shizuka spots Rentarou talking with Hakari and Karane and, seeing them acting romantically with one another, thinks he's no longer interested in her and reflects on how badly she was treated growing up due to not talking verbally. However, Rentarou drops by the library later that day and gifts her with a text-to-speech app for her phone containing the entire text of the book she lent him, allowing her to maintain eye contact with the people she talks to instead of having them read from her book. Using the app, Shizuka reveals that she knows about Rentarou's current girlfriends and believes he won't love her like he does Hakari and Karane. Rentarou assures her that he will love her as much as she wants to be loved, and gives her a hug.
When Rentarou introduces Shizuka to the other girls, Karane immediately flips out, but Hakari is flattered that he has a new girlfriend. Rentarou attempts to placate their fears of not being loved by promising to commit Seppuku if he can't be a good boyfriend.
Rentarou introduces Shizuka to Hakari and Karane, the latter of whom is surprised by Shizuka using a text-to-speech app to communicate. After Shizuka tests out saying the other girls' names, Rentarou describes the girls' Character Tics that not even the girls themselves notice. This soon leads to Rentarou letting slip that he had kissed Hakari and Karane, shocking Shizuka. Rentarou offers to give Shizuka a kiss, but she refuses, so Rentarou decides to take things at a pace Shizuka feels comfortable with.
In order to break the ice for Shizuka, Rentarou proposes a game of Old Maid with a Friendly Tickle Torture penalty game. Rentarou wins the first three rounds, each of which leaves a different girl in last place. Karane fights to keep from laughing, Hakari has to be told not to undress for her penalty, and Shizuka uses her app to "laugh".
The fourth game ends with Rentarou in last place and Shizuka in first place. Her tickling amounts to nothing more than gently poking him repeatedly. After she finishes, Rentarou leaves to go to the bathroom, whereupon Karane confronts Shizuka, much to the latter's confusion.
Karane lambastes Shizuka for holding back on tickling Rentarou despite wanting to go further. Shizuka is reluctant to do anything that could interfere with Hakari or Karane, and she explains that she's scared of Rentarou thinking less of her than the other girls. Karane assures Shizuka that she has nothing to fear and apologizes for chewing her out.
Rentarou, meanwhile, had been observing the trio through the window, having noticed Karane's reaction to Shizuka poking him instead of tickling him and leaving in order to let the girls sort out their insecurities freely. Returning to the roof, Rentarou is told to have Shizuka redo the penalty game. Shizuka, however, decides she's ready for a kiss with Rentarou. The two of them kiss, and Rentarou kisses Hakari and then Karane after that. Rentarou muses that he doesn't feel deserving of such happiness, with each girlfriend feeling the same way.
Rentarou recounts the first time he fell in love with a girl. When he was eight months old, he hurt himself when he knocked over a building block tower, and a baby girl comforted him. The two began spending time together, but when Rentarou confessed to her, she got scared and crawled away.
For the next several years, he made efforts to improve himself in the hopes of becoming someone's ideal boyfriend, getting rejected by girl after girl after girl over and over again.
Thinking about his life story brings Rentarou to tears, prompting his girlfriends to comfort him.
- Abusive Parents: Shizuka's mother lashed out at her for her reluctance to communicate verbally.
- Accidental Pervert: During the kissing game, Rentarou accidentally gropes Hakari. Unlike most outcomes of this trope, she actually welcomes it.
- Awesome, but Impractical: Rentarou spends several nights typing up the full text of Shizuka's book for the text-to-speech app, when a sensible person would download an e-book or Kindle version for said app.
- Big Damn Kiss: Having finally gotten over her insecurity, Shizuka finally secures a kiss with Rentarou.
- Bland-Name Product: Amazen Prime, which Rentarou is looking up to buy a weapon to commit seppuku with should he disappoint his girlfriends."Dagger Punishment As painful as possible before certain death"
- Boring, but Practical: The three-way kiss proves to be the most effective option for Rentarou kissing Hakari and Karane without either feeling jealous of the other.
- Brick Joke:
- Rentarou looking up something to commit Seppuku with online, just like he said he did in Chapter 3.
- The God of Love getting distracted by Castle in the Sky while doing paper work. No doubt Rentarou's.
- Clingy Jealous Girl: Shizuka briefly falls into this when Rentarou mentions having kissed Hakari and Karane already.
- Crash-Into Hello: Rentarou's first encounter with Hakari and Karane.
- Early-Bird Cameo: Shizuka and Nano walk past Rentarou in the hall right before he crashes into Hakari and Karane.
- Establishing Character Moment: Rentarou's convoluted kissing game shows the lengths he would go to in order to keep his girlfriends happy.
- Establishing Series Moment: The God of Love reprimands Rentarou for repeating everything he says, as he's wasting panels, establishing that the manga has No Fourth Wall. Also, Hakari and Karane quickly warm up to Rentarou dating both of them at the same time, establishing that none of the girls will be jealous of anyone else dating Rentarou.
- Eye Scream: Karane jams a cookie and a bocky stick into Rentarou's right eye in a bashful attempt at Romantic Spoonfeeding.
- Foreshadowing: Hakari claims that her household checks body temperature through kissing. Seeing what her mother is like after we meet her suggests that Hakari might not have entirely made it up.
- Friendly Tickle Torture: Rentarou uses this as an icebreaker for Shizuka, since newcomers are more open to people who have shown their true feelings to them, and laughter is one of the more difficult reactions to suppress.
- If It's You, It's Okay: Hakari's reaction to the Accidental Pervert moment mentioned.
- Imminent Danger Clue: Rentarou notices Karane glaring while Shizuka is poking him, and leaves so that she can vent her frustrations with Shizuka holding back.
- Irony: During Shizuka's confession, Rentarou references a scene from her favorite book where two Star-Crossed Lovers decided that they would have to defy fate to be together, no matter what obstacles stood in their way. This serves to reassure Shizuka that she could still be with Rentarou, even though he already had two girlfriends. However, Rentarou knows full well that their initial Love at First Sight was due to being destined soulmates. His epiphany revolved around realizing he truly loved Shizuka, rather than
being "obligated" to care for her because of his destiny. - Love Epiphany: Rentarou realizes during Shizuka's confession that the love he has for his soulmates is genuine, and not Because Destiny Says So or because he doesn't want them to die.
- Love Hurts: Played for Drama. Rentarou's constant rejections throughout his life had caused him actual, unfunny emotional pain. To the point where he wished that he wasn't a Love Freak and cried thinking about it.
- Oblivious to Her Own Description: Karane doesn't notice when she's raising her voice.
- Sacred First Kiss: The plot of Chapter 2 hinges on who Rentarou gives it to.
- Shout-Out:
- Rentarou's soulmate count was racked up by two orders of magnitude because the God of Love was watching Castle in the Sky while filling out his paperwork.
- Rentarou calls the God of Love a Tokyo Ghoul.
- Two to Kinnikuman. First, in the kissing failure montage, one instance has Karane giving Rentarou a Kinniku Buster. Later when Karane puts the vice principal in a Camel Clutch, Rentarou starts to call her Ramenman.
- Sprouting Ears: Karane sprouts cat ears and a cat tail when she spots a cat.
- Suicide as Comedy: Rentarou offers to kill himself if his girlfriends aren't satisfied with him.
- Summon Magic: The three-way kiss at the end of Chapter 2 actually summoned a UFO.
- Time Skip: None of the hands of Old Maid are given any details; only the outcome of each hand is spelled out for the readers.
- Unprovoked Pervert Payback: Karane keeps thinking Rentarou is going further than a kiss during the game, causing her to give him a beatdown when he approaches her.
- What Is This Thing You Call "Love"?: Inverted. Rentarou has spent most of his life thinking of nothing but love.
- Wounded Gazelle Gambit: Hakari pretends to have hurt her leg from the Crash-Into Hello as an excuse to flirt with Rentarou, with Karane flusteredly following suit.
