Yume Nijino and her friend Koharu Nanakura, who want to join the top idol group S4, enroll at the idol school Yotsuboshi Academy, where the four members of S4; Hime Shiratori, Yozora Kasumi, Yuzu Nikaidou, and Tsubasa Kisaragi, study.

As word spreads about Yume's performance, despite Yume herself being unable to remember what happened or repeat any of the prowess she showed in class, she and Koharu check out the various classes they can audition for.

With the class sorting auditions approaching, Yume worries that she isn't good enough to join the Song Class.

The first year students in the Song Class are tasked with working backstage at Aikatsu TV, setting up a stage for a fashion show that Hime and Yozora are appearing in.

The students are tasked with using the Dress Make system to design their own dresses.

Yume, Koharu, and Rola decide to enter an audition for a drama starring S4, despite none of them having acted before.

Rola enters an audition searching for individualistic idols to be the mascot of an ice-cream company.

As a fashion model contest is held for the Beauty Class first-years, Koharu befriends her classmate, Mahiru Kasumi. Koharu becomes hesitant to enter the audition, feeling she is lacking compared to everyone else, but Yume and Rola encourage her to have more confidence in herself.

Yume and Rola are selected to represent Yotsuboshi Academy in an open audition for a confectionary campaign girl, competing against idols from other schools.

Yume is requested by the school's headmaster, Hikaru Moroboshi, to hold her first solo concert after Hime's concert gets cancelled.

As an apology for the trouble caused by her concert's cancellation, Hime offers Yume the chance to be her manager for the day, as a television crew documents her schedule.

Following a performance together, Yume and Rola encounter a scary creature on their way back to their dorms, where they face a punishment from Tsubasa for being late.

Yotsuboshi Academy puts on an original movie in which Yume stars as a small fairy. Learning that her sister, played by Hime, has been kidnapped by a demon lord, Yume goes off towards his castle, coming across various allies along the way including M4's Nozomu.

Yozora announces a contest for students to design their own dress for Romance Kiss and wear it in a special performance. While exploring town for ideas, Yume, Rola, and Koharu come across both Yozora and M4's Asahi, who are both revealed to be Mahiru's siblings.

As the top scorers of their respective classes, Rola, Ako, and Mahiru, along with the Dance Class' Luka Haruka, are chosen to pair up with the S4 members and compete in a Summer Fest tournament with lunch coupons up for grabs.

While out doing a commercial shoot on the morning of the second day of Summer Fest, a camera malfunction puts Rola at risk of not making it back in time for her performance with Hime.

Yume, Koharu, Rola, and Ako appear on M4's variety show. As Ako remains intent on getting Subaru's attention, she is warned by Kanata Hira to keep things under control and treat her fellow idols as equals whilst on air.

The girls hear about the Fresh Idol Election, in which the first-year idols will be ranked by fan votes, with the top four idols appearing in the upcoming Aikatsu Island event.

Hoping to help Koharu with her heat exhaustion, Yuzu invites the girls to a Dance Battle tournament that she is participating in.

Yume and the others sneak onto the set of a movie that Tsubasa is starring in alongside the rest of S4. During the shoot, Tsubasa gets a lot of slack from the lead actor, Taiyou, who seems to have lost his passion for acting.

As the Song Class are faced with an audition to make their CD debut, putting Yume and Rola is direct competition with each other, they are required to wear weighted clothing during their training.

Due to Moroboshi's meddling, Yume is given only a short amount of time to record a mini-album for her debut CD, with Hime's new album planned for release on the same day.

Wanting to find her own individuality, Yume and the others go searching for seven "luckies" around the school said to grant wishes.

After giving a group performance, Yume, Rola, Mahiru, and Ako are given a three day break from their activities. Learning that Yume's family runs a well known bakery, the girls all go to Yume's house to try their pastries.

As students are given roles in a Broadway Dream production for the upcoming school festival, Koharu is selected as a show dancer for one of the musical numbers.

A new school year begins with Yume now a fully-fledged S4 member alongside Ako, Mahiru, and Yuzu. As Yume launches her new brand, Berry Parfait, Ako is shocked to learn that the brand she was hoping to pair up with, Fuwafuwa Dream, has instead announced a contract with Kirara Hanazono, an idol from the ship-based idol school Venus Ark.

As the threat of Venus Ark looms over the school, Yume and Rola decide to put on a show for the first year students.

In trying to come up with a dress idea to rival Elza's Star Wings, Yume is told by her brand owner to think about what she herself would enjoy.

Wanting to take back Fuwafuwa Dream from Kirara, Ako sneaks into their headquarters with Yume and competes with Kirara to design the brand's new Premium Rare Dress.

Upon arriving at Venus Ark, Yume, Rola, and Mahiru are greeted by Koharu, who explains how she was scouted as a designer by Elza during her studies in Italy.

While doing modelling work, Mahiru hears about a mysterious model known as Shooting Star who vanished from the public eye one day.

Looking to relieve some boredom, Kirara decides to tag along with Yume and Rola as they do a report show on various spots around town.

Koukadou holds another audition for a new campaign unit, which Yume, Lily, Elza, and Kirara all receive invitations to.

As Yume struggles to come up with a Premium Rare Dress for her brand due to her busy schedule, Koharu decides to hold a fishing contest for a change of pace.

Yume and the others decide to do a feature on Elza for S4's show, during which they are escorted by a first-year student named Alice Caroll. Just as the feature gets underway, Elza suddenly tells Alice that she is to be expelled at the end of the day due to her declining popularity.

Ako is excited to be starring in a drama alongside Subaru, but struggles to keep her composure in front of him during a confession scene with him.

Tsubasa announces her plans to study abroad before informing Rola that she will inherit Spice Chord on the condition that she pass a series of tests.

As S4 are each given surprise one-day jobs for their program, Lily decides to becomes a guide for a fan tour to Suzukaze Plateau in leau of resting at her summer retreat.

With Tanabata approaching, Elza has Rei come out of retirement and resume model work as Shooting Star.

As Rola begins her duties as Spice Chord's muse and works on her own Premium Rare Dress, she and Yume are invited to be part of a Venus Wave event to increase their Aikatsu Ranking.

While preparing for her own performance, Yume comes across a young girl named Saya whose friends keep arguing over which idol is better.

Yuzu decides to hold a treasure hunt at the pool for her Shiny Smile brand's Premium Rare Dress premiere.

Venus Ark prepares to hold its proficiency tests, with Kirara sharing a rumor of a forbidden room on the ship where those who fail their tests are locked away.

While en route to preparations for the newest Aikatsu Island event, Yume, Rola, and Mahiru come across three idols from Starlight Academy; Akari Ozora, Sumire Hikami, and Hinaki Shinjō.

While kayaking in the sea, Yume, Rola, and Koharu get lost in a fog storm and end up on a remote island, where they come across Ichigo Hoshimiya.

Elza tells Koharu that the Venus Ark will be leaving Japan for a tour. Meanwhile, Yume, Rola, and Mahiru, whose exchange programmes aboard the Venus Ark are scheduled to end as a result, assume that they will end up having to part ways with Koharu once again, becoming worried when they can't find her aboard the ship before it departs.

Koharu wants to help Yume design some dresses for Berry Parfait, but can't find the confidence to ask her.

Noticing something off between Yume and Koharu, the other girls learn that they had gotten into an argument about Koharu's dress designs.

Yume and Koharu are scheduled to appear on a children's animal show hosted by Ako, where Kirara also brings her pet sheep, Caroline.

Learning that her parents are finally getting some time off work, Mahiru returns home with Yozora and Asahi to spend some quality family time together.