The story is very shoujo inspired, and centers around the love lives of a group of friends in 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 so 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 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.
Most songs in the series are sung by GUMI and Hatsune Miku and so far, all of the songs on Niconico that had been done with Vocaloids have entered the Hall of Fame, with most of them having reached over a million views in their YouTube uploads. 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.
Aside from the songs, the ~Love Series~ has six novels released so far that expand on the cast's interactions throughout the songs: "Confession Rehearsal", "A Solution for Jealousy", "First Love Picture Book", "Falling in Love Now.", "Blooming into the Color of Love", "Friday's Good Morning.", and "Assertion of the Heart". A dubbing planning and a digest video have been uploaded for "Confession Rehearsal", dubbing planning has also been uploaded for "A Solution for Jealousy", and a preview has been uploaded for "Romeo".
The series is featured on four of HoneyWorks' albums, but only three of them (Boku Ja Dame Desu Ka? , Suki ni Naru Kono Shunkan wo. and Nandodatte, Suki.) are officially specific to the series. However, each CD comes with a vomic- 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.
This song focuses on the new character Koyuki, who previously had short appearances in Embarrassment-Hiding Adolescence and Diagnosis: Lovesickness. He developes a crush on Natsuki and declares Setoguchi his "Rival".
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 Mio to be by his side. Apparently, he is half-joking at this particular moment in time.
Profile: He's mischievous, but loves helping people. He doesn't talk to girls often, and mostly hangs out with guys instead. He's surprisingly methodical and can be sensitive.
Siblings: Older Brother who is a fully fledged adult.
Song focus: First Love Picture Book (indirectly), A Teacher, Detained, Goodbye to Our Mutual Unrequited Love (indirectly), Tokyo Summer Session, Propose.
Birthday: April 5th (Aries) / Blood type: A / Height: 175 cm / Voiced by:Kenichi Suzumura.
Profile: She's shy and isn't the type to stand out, but she's kindhearted and has a lot of friends. She doesn't talk to guys a lot with the exception of Haruki.
Siblings: Only child.
Song focus: First Love Picture Book, Goodbye to Our Mutual Unrequited Love (indirectly), Future Chart, Tokyo Summer Session, Propose (indirectly).
Birthday: March 20th (Pisces) / Blood type: A / Height: 153 cm / Voiced by:Aki Toyosaki.
Profile: Kind to both guys and girls alike. Unaware of his popularity. Though many people like him, he isn't very interested (or doesn't notice). He can sometimes be sulky and indecisive.
Siblings: Younger sister in first year of high school.
Song focus: Confession Rehearsal (indirectly), Confession Rehearsal -another story-, Embarrassment-Hiding Adolescence, Diagnosis: Lovesickness (indirectly), Falling in Love Now. (indirectly), Tokyo Summer Session.
Birthday: July 11th (Cancer) / Blood type: AB / Height: 178 cm / Voiced by:Hiroshi Kamiya.
Profile: Bright, assertive, and loves sports. Eats a lot. She wants to boost her femininity, but wears track pants under her uniform skirt all year around. (Her friends tell her to wear them to make moving around easier).
Siblings: Younger brother in first year of high school.
Song focus: Confession Rehearsal, Confession Rehearsal -another story- (indirectly), Diagnosis: Lovesickness, Confession Rival Declaration (indirectly), Falling in Love Now. (indirectly), Tokyo Summer Session.
Birthday: June 27th (Cancer) / Blood type: 0 / Height: 161 cm / Voiced by:Haruka Tomatsu.
Profile: Ernest and straightforward. His feelings are pure, but he tends to get jealous. Since he has a childish face, his friends make fun of him. His nickname "Mochita" comes from combining his name and the word "yakimochi" (jealousy).
Siblings: Older sister in college and younger sister in elementary school.
Song focus: A Solution for Jealousy, A Solution for Jealousy -another story- (indirectly), Tokyo Summer Session, The Day When I Call Your Name, The Day When I Know Love (indirectly).
Birthday: September 3rd (Virgo) / Blood type: B / Height: 165 cm / Voiced by:Yuuki Kaji.
Profile: Oblivious in the matters of love and crushes. She's shy but has a friendly smile, which makes her popular. Airheaded. Not very good at sports.
Siblings: Older sister in college.
Song focus: A Solution for Jealousy (indirectly), A Solution for Jealousy -another story-, Tokyo Summer Session, The Day When I Call Your Name (indirectly), The Day When I Know Love.
Birthday: December 3rd (Sagittarius) / Blood type: 0 / Height: 158 cm / Voiced by:Kana Asumi.
Profile: Setoguchi Yuu's younger sister, in her third year of middle school. Has an emotional and cheerful personality. At home, she acts rough and can sometimes be a bit careless.
Siblings: Older brother in third year of highschool.
Song focus: Embarrassment-Hiding Adolescence, Confession Rival Declaration (indirectly), Falling in Love Now., Falling in Love Now -Triangle Story- (indirectly), Triangle Jealousy (indirectly), It Was Supposed to be Hate.
Birthday: August 8th (Leo) / Blood type: A / Height: 149 cm / Voiced by:Momo Asakura.
Song focus: Embarrassment-Hiding Adolescence (indirectly), Confession Rival Declaration, Falling in Love Now. (indirectly). Falling in Love Now -Triangle Story-(indirectly), Triangle Jealousy (indirectly).
Birthday: August 28th (Virgo) / Blood type: A / Height: 163 cm / Voiced by:Tsubasa Yonaga.
Song focus: A Teacher, Detained.
Birthday: May 29th (Gemini) / Blood type: O / Height: 183 cm / Voiced by:Hikaru Midorikawa.
Siblings: Older sister in third year of highschool.
Song focus: Falling in Love Now. (indirectly), Sankaku Jealousy, Falling in Love Now -Triangle Story-, It Was Supposed to be Hate.
Birthday: November 29th (Sagittarius) / Blood type: B / Height: 160 cm / Voiced by:Natsuki Hanae.
Siblings: A younger sister.
Song focus: Friday's Good Mornings (indirectly), Friday's Good Mornings -another story-, Sunday's Secret, Romeo (indirectly).
Birthday: October 16th (Libra) / Blood type: B / Height: 160 cm / Voiced by:Sora Amamiya.
Song focus: Friday's Good Mornings, Friday's Good Mornings -another story- (indirectly), Sunday's Secret.
Birthday: January 23rd (Aquarius) / Blood type: A / Height: 169cm / Voiced by:Gero.
Song focus: Mean Encounter (indirectly), Assertion of the Heart
Birthday: February 3rd (Aquarius) / Blood type: B / Height: 150cm / Voiced by:Nao Toyama.
Profile: Koutarou's flirtatious friend, and a known playboy among the school.
Song focus: Mean Encounter.
Birthday: April 1st (Aries) / Blood type: O / Height: 167cm / Voiced by:Yoshimasa Hosoya.
Profile: A studious boy with glasses, part of the "Idiot Trio" formed by himself, Shibasaki, and Koutarou. Often makes observations about the situations at hand.
Song focus: N/A
Birthday: November 7th (Scorpio) / Blood type: A / Height: 172cm / Voiced by:Yoshitsugu Matsuoka.
Profile: A young girl in her first year of high school, having just moved to Tokyo from the countryside. She first appears in Blooming into the Color of Love at the very end as a preview for her own arc.
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.
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 together and aired for six weeks starting from November 2017.