The 1,088th episode of Detective Conan begins with an incident at Doterasu Shrine. A young man named Okamoto Jupita, a 20-year-old college student, is pushed down the stairs by an unknown assailant. The Detective Boys, who are present at the scene, call an ambulance and the police.

Jupita is taken to Beika Central Hospital, where his older sister, Okamoto Juria, an aspiring songwriter, is informed about the incident. Juria wonders why her brother was in Beika City, as he had told her he was in Waiha City, which is in the opposite direction.

The plot thickens when it is revealed that Juria and her mentor, Saimon Kotaro, a veteran songwriter, share a past connection to Beika City. Both harbor resentment toward Kariba Yuzuru, a successful songwriter who lives in Beika City. Kariba is accused of plagiarizing lyrics and slandering Saimon. Juria also reveals that she broke off her engagement with her ex-fiancé Mizutani Ren because he refused to move out of Beika City after Kariba relocated there.

The Detective Boys begin investigating why Jupita was in Beika City. They find a receipt in his pocket from a general store near the train station, indicating he had purchased a knife. However, the knife is not found on him. Instead, it is discovered in a daypack at the shrine, along with a scarf that wasn’t there before.

The investigation leads to a shocking revelation. It is suspected that Jupita may have planned to kill Kariba. The evidence includes the knife, a threatening call made to the Songwriters Association, and Jupita’s presence in Beika City. However, Conan finds inconsistencies in this theory.

Conan concludes that another person, referred to as "X," actually planned to murder Kariba and frame Jupita for it. This person drugged Jupita, took his scarf, and made the threatening call. However, when Jupita was hospitalized after being attacked by a mugger, X abandoned the plan.

In a surprising twist, it is revealed that Saimon is Person X. He admits to his scheme but is relieved to learn that Kariba has been arrested for tax evasion and will be investigated for plagiarism.

Meanwhile, it turns out that Jupita visited Beika City to cook for Mizutani, hoping to reconcile him with Juria. His actions were misunderstood due to the circumstances, leading to suspicions that he was plotting murder.

The episode ends with Saimon deciding to turn himself in for his actions, and the Detective Boys promise to visit Jupita in the hospital.