"Shigatsu wa Kimi no Uso" centers on Kōsei Arima, a former child prodigy pianist who loses his ability to hear the sound of his piano after the death of his emotionally demanding mother, Saki Arima. Traumatized by her passing and the pressure she placed on him, Kōsei abandons music and lives a monotonous life, devoid of passion. His world changes when he meets Kaori Miyazono, a free-spirited violinist whose unconventional and vibrant approach to music contrasts sharply with Kōsei's rigid, technical style. Kaori's insistence that Kōsei accompany her in a competition reignites his connection to music, though he struggles with self-doubt and the lingering shadows of his past.

As Kōsei gradually rediscovers his love for the piano, the series explores his relationships with those around him. Tsubaki Sawabe, Kōsei's childhood friend, harbors unspoken feelings for him but struggles to reconcile her emotions with her desire to see him happy. Ryōta Watari, another friend and Kaori's supposed love interest, provides a grounded perspective on their group dynamic. The narrative delves into themes of loss, self-discovery, and the transformative power of art, as Kōsei learns to confront his fears and embrace his identity as a musician.

Kaori's own story unfolds as a poignant counterpoint to Kōsei's journey. Her seemingly carefree demeanor masks a deeper struggle, revealed later in the series, which adds emotional weight to her interactions with Kōsei and her performances. The series balances moments of humor and warmth with profound emotional depth, culminating in a narrative that intertwines the characters' growth with their shared love for music. Through competitions, recitals, and personal revelations, "Shigatsu wa Kimi no Uso" portrays the complexities of human relationships and the enduring impact of art on the soul.