Episode 2 of "Glass Heart" kicks off with the mesmerizing tune of Tenblank's debut song, "Matrix," sending the crowd into a frenzy of cheers. Yet, amidst the exhilaration, Akane finds herself trapped in a whirlwind of thoughts. Naoki, sensing her turmoil, urges her to let loose. And indeed, during their second number, "Crystalline Echo," Akane shines brighter, earning a commendatory nod from Kazushi amidst the thunderous applause.
Amidst the sea of adoring fans, a figure named Ichidai Isagi lurks, whispering to his accomplice about allowing Naoki to soar before reclaiming him.
Later, Naoki drops a bombshell on his bandmates, announcing their imminent recording of a single within the next three days. On a leisurely stroll, Akane can't help but admire a poster featuring the enigmatic singer, Sakurai Yukino. Little does she know that Yukino shares the same manager as Isagi.
As the recording sessions commence, Naoki's dissatisfaction with Akane's drumming becomes evident. He implores her to showcase the fire he knows she possesses. Kazushi, stepping in to comfort Akane, dismisses Naoki's critique lightly, confessing his own puzzlement over Naoki's recruitment when he could effortlessly create music solo. He encourages Akane to prove her worth to Naoki, just as he once did.
A sudden visit from Yukino and Isagi to the recording studio stirs the pot further. They propose a collaboration between Naoki and Yukino for her upcoming album, a suggestion Kai vehemently opposes. However, Naoki stands his ground, asserting his independence.
Meanwhile, Akane struggles to meet Naoki's expectations. Arriving at the studio one morning, she discovers Naoki has been toiling all night. Despite the others' reassurances that the song is flawless, Naoki remains steadfast in his quest for perfection.
Akane confronts Naoki, accurately deducing his underlying issue with Isagi. Naoki confesses that he bears some responsibility for transforming Isagi into the man he is today. Reassuring Akane, he vows not to let her down.
At her home, Akane plunges into her drum practice with unprecedented determination. One day, she ventures into the recording studio and encounters Toya, who is engrossed in playing the piano. He dares her to take on the drums, and she eagerly complies, only for him to abruptly halt the session. He critically informs her that her drumming now mirrors Naoki's style rather than her own unique flair. Once more, he issues a stark warning: either she risks diluting Naoki's sound or he will crush her spirit.
Following another rehearsal where Toya dismissively brushes aside Akane's skills, he casually orders her to fetch him some food. Over a bowl of noodles, Toya reveals a startling piece of information to Akane: Naoki abandoned music years ago after someone stole one of his songs, leading the thief to eventually lose both their talent and reputation. Their conversation is interrupted by the sight of Naoki outside the noodle shop. As the trio walks together, Toya probes Naoki about whether he made a deal with Isagi and then taunts him by predicting that he will be like John Lennon, who created countless masterpieces but died young. Akane looks worried and leaves in a hurry.
Naoki pursues her and hands her a flash drive containing the bass recording. Akane, eyes searching his, asks if she possesses what it takes to do justice to his music. He counters with a poignant question of his own – if he were to pass away the very next day, would she continue to play the drums? Silenced for a moment, she dashes across the road, resolute in her reply: she would indeed persist. However, she expresses her heartfelt wish that he should not meet the same fate as John Lennon.
The next day, Naoki expresses his approval of Akane's studio recording. The new single is soon polished to perfection, ready to be unleashed upon the world!
