The story is very shoujo romance inspired, and centers around the love lives of several groups of students in Sakuragaoka high school and how they handle their growing feelings as time passes. However, the main focus shifts often.
The first section of the story is centered on the six person group of Yuu, Natsuki, Haruki, Miou, Souta, and Akari. Yuu and Natsuki get together first and remain together for the rest of the series, Souta and Akari can't on the boundary that Akari isn't quite sure what love exactly is and Souta is too nervous and insecure to ask her out, and Haruki and Miou are both in love with each other, but cannot and do not admit it to each other for their entire high school career. Later songs give proper introductions to other potential couples and their relationship woes, who form a secondary group-- Koyuki, a friend of Souta's who changes his appearance in the hopes of winning over Natsuki; Yuu and Natsuki's siblings Hina and Koutarou, who are in a one-sided love triangle because of Hina's affection for Koyuki and Koutarou's crush on Hina; Sena and Midori, a teen model and another student who want to get together but can't approach each other the way they want to; and Ken and Arisa, a playboy and friend of Koutarou and the outspoken girl who didn't initially fall for his charms. The songs would also introduce LIP×LIP, an idol duo who end up the classmates of Hiyori, a student unfamiliar with city life, who are often promoted separately.
Most songs in the series are sung by GUMI and Hatsune Miku and so far, most of the songs on Niconico that had been done with Vocaloids have entered the Hall of Fameand a handful in the Hall of Legend, with most of them having reached over a million views in their YouTube uploads. They stopped ranking sometime after "Tokyo Summer Session" released due to the switch to human vocals. There are, however, a number of songs in the series (both in-canon and as bonuses) that are sung by various groups and the cast's voice actors that are available on the CD sets and the official accounts.
In 2019, the song series began a spinoff focused on the idols, appropriately titled the Idol Series.
Aside from the songs, the ~Love Series~ has ten novels released so far that expand on the cast's interactions throughout the series: "Confession Rehearsal", "A Solution for Jealousy", "First Love Picture Book", "Falling in Love Now.", "Blooming into the Color of Love", "Friday's Good Morning.", "Assertion of the Heart", "Mean Encounter" "The Day When I Called Your Name", and "Thank You For Choosing Me."/"I Was Supposed to Hate You."
The series is featured on all four of HoneyWorks' studio albums, but only two of them (Boku Ja Dame Desu Ka? and Nandodatte, Suki.) are officially specific to the series and feature a selection of relevant character songs, and only one of these albums is completely Vocaloid involved. Each CD comes with a short comic - Zutto Mae Kara Suki Deshita., with a special edition that included the vomic for "Confession Rehearsal"; Boku Ja Dame Desu Ka?, with a special edition that included the vomic for "A Solution for Jealousy"; Suki ni Naru sono Shunkan wo., with a special edition that includes the vomic for "Falling in Love Now."; and Nandodatte, Suki., which includes a vomic for "Romeo". The vomics serve as a "prologue" to the content of the songs, and also help expand on character interactions and plot threads. Online, the dubbing planning and a digest video for "Confession Rehearsal", the a digest for "A Solution for Jealousy", and the preview for "Romeo" are officially available. "Falling in Love Now."'s video is also available for viewing.
Four Vocaloid singles have also been produced for the series: Boku ga Namae wo Yobu Hi/Watashi ga Koi wo Shiru Hi, which acts as a sequel to A Solution for Jealousy; Judge☆/Tsuki no Hime, which acts as Yuujirou and Aizou's debut CD both in and out of universe; Choco-Kano / White Day Kiss, another LIP×LIP CD but not credited as a major single for the duo; Erande Kurete Arigatou. / Love-Hate Majority, a sequel to "Daikirai na Hazu Datta." and a side story focusing on Serizawa Chiaki and Akechi Saku respectively; and Heroine Ikusei Keikaku /Koibito-tachi no Happy Birthday featuring a character song for Hiyori Suzumi and a birthday song. LIP×LIP also has one complete album, Docchi no kiss ka, Erabe yo., containing most of the various songs made for them over the course of their first two years.
The song Inokori Sensei is especially notable for being used as the debut demo for the VOCALOID flower. Likewise, Romeo is notable as LIP×LIP's debut song.
This song focuses on the relationship between Natsuki and Yuu, with Natsuki trying (and eventually succeeding) to confess to him. Officially seen as the first song in the series despite coming out second.
The sequel to Friday's Good Morning, from the perspectives of both Sena and Midori. They exchange phone numbers at first and go on a Sunday get-together to an amusement park, but over the course of weeks they finally begin dating each other in secret.
Aizou and Yuujirou's official introduction. Most of the song appears to be an in-universe music video with Sena as the centerpiece, having Yuujirou and Aizou compete for her. Hiyori also makes a cameo.
A short, PV-less song with Miou and Haruki as teenagers on the cover, indicating the song is about them. The pair spend a night under the stars, until Haruki asks Miou to be by his side. Apparently, he is half-joking at this particular moment in time.
Ten novels have been released so far, with the draft ideas being by HoneyWorks and the writing by Fujitani Touko (vol. 1-6) and Kousaka Mari (vol. 6-present), while the illustrations were provided by Yamako. There are also three novelizations of the animated features listed below, penned by the latter author.
The cover of the first novel "Confession Rehearsal"
The cover of the second novel "A Solution for Jealousy"
The cover of the third novel "First Love Picture Book"
The cover of the fourth novel "Falling in love Right Now."
The cover of the fifth novel "Blooming into the Color of Love"
The cover of the sixth novel "Friday's Good Morning"
Cover of the ninth novel "Assertion of the Heart"
Tenth Novel, "Mean Encounter"
Eleventh Novel, "The Day When I Called Your Name"
The cover of the "I've Always Liked You" novelization
Starting in Spring 2016, the series also had its share of full fledged animated adaptations after getting animated snippets in the vomics. The first of them was "I've Always Liked You" (Zutto Mae Kara Suki Deshita.), adapting Natsuki and Yuu's storyline and "A Solution for Jealousy". The second, "The Moment You Fall in Love" (Suki ni Naru Sono Shunkan wo.), came out in December 2016 and adapts Hina's series of songs. Both of these are feature length films.
In 2017, the series was announced to have an animated television special. Titled Itsu Datte Bokura no Koi 10 Centi Datta. (We've Always Been 10 Centimeters Apart.), it centers around Mio and Haruki's arc and aired for six weeks starting from November 2017. All of these properties share voice actors with the vomic cast.
A stage play adaptation adapting the series came out in spring 2019, produced by Stage Project ILLUMINUS. Titled 70-oku Bun no 1 no Koi, it looks to adapt the Confession Rehearsal, A Solution for Jealousy, and First Love Picture Book arcs. This adaptation also adds a few original schoolmates that were not seen in other adaptations.