The Summer Hikaru Died episode 1: The truth behind Hikaru’s death is explained as a mysterious being assumes his identity

Released on Sunday, July 6, 2025, The Summer Hikaru Died episode 1 opens by revealing the tragic moment Hikaru died in the mountains as he encounters a mysterious entity. In the present, Yoshiki confronts the impostor now living as Hikaru, realizing it’s not the friend he once knew.

The being, later identified as Nonuki-sama, admits it doesn’t wish to harm Yoshiki and expresses a desire to keep living as Hikaru. As Yoshiki struggles to accept the truth, strange occurrences begin unfolding in the village, culminating in a mysterious death that hints at a deeper threat. Meanwhile, a group of outsiders investigates the supernatural events, setting the stage for a larger story to unravel.

The Summer Hikaru Died episode 1 shows how Hikaru died and the imposter takes his place

Hikaru in his final moments in The Summer Hikaru Died episode 1 (Image via CygamesPictures)

The Summer Hikaru Died episode 1, titled Replacement, opens in January 2020 in Nishimiya, where a desperate Yoshiki is frantically searching the forest for his missing friend, Hikaru. While the others choose to turn back, Yoshiki refuses to give up.

Deep in the forest, Hikaru is shown lying injured, crying out for Yoshiki as a mysterious entity looms near him. Referring to it as "Unuki-sama," just as Hikaru reaches his hand forward for help, the entity consumes him.

The story then jumps forward to July 2020 in Kubitachi Village, where Hikaru and Yoshiki are seen sharing a Papicco during a sizzling summer day. They chat about Hikaru’s disappearance on the mountain. He was gone for a week, but claims to remember nothing.

The fake asks Yoshiki to keep the secret (Image via CygamesPictures)

Out of the blue, Yoshiki confronts him, saying what he’s suspected for a while— the person standing before him isn’t the real Hikaru. Caught off guard, Hikaru admits he’s an impostor, surprised Yoshiki could tell despite his perfect mimicry. The strange entity slips from his left eye and approaches Yoshiki, pleading with him to keep the truth hidden.

The being confesses that this is his first time living as a human, and although he knows the body and memories aren’t his, he truly likes Yoshiki and doesn’t want to kill him. Faced with the painful truth that the real Hikaru is truly gone, Yoshiki decides to protect the secret. Despite everything, he tells the impostor he wants him to stay.

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In The Summer Hikaru Died episode 1, the narrative shifts between flashbacks of Yoshiki and the real Hikaru, and glimpses of their time together, including a conversation in which Hikaru mentions heading to the mountain but withholds the reason. In the present, Yoshiki awakens from dreams of these memories, still haunted and heartbroken.

Though he tries to move on, the weight of loss lingers. Hikaru arrives to walk to school with him, and Yoshiki silently convinces himself he can live with the fake because letting go of Hikaru completely is something he just can't do.

The Summer Hikaru Died episode 1: The being is introduced as Nonuki-sama while a bigger story begins

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The Summer Hikaru Died episode 1 then shifts elsewhere. A man named Tanaka arrives at a house, carrying a hamster and claiming he’s there on behalf of his company. Using the hamster to probe for something abnormal, Tanaka uncovers a monster-like entity in the cupboard, where the wall has eyes and a mouth. As the creature calls out "mommy," Tanaka swiftly neutralizes it.

Afterward, Tanaka calls a woman to report that the creature had no connection to "that thing." She’s visibly disappointed, while Tanaka laments that despite their company’s centuries-long search, they still haven’t located it, admitting it won’t be easy to find.

Meanwhile, at school, Yoshiki observes the fake Hikaru’s growing excitement toward things like music and movies. Hikaru even shares that he enjoys singing and finds himself curious about the meaning behind song lyrics. After school, Hikaru tells Yoshiki why everything excites him.

Hikaru and Yoshiki in The Summer Hikaru Died episode 1 (Image via CygamesPictures)

Despite having Hikaru’s memories, it’s his first time experiencing life firsthand. Yoshiki asks what the entity was before it took over Hikaru’s body, but it admits it doesn’t know. As a cat nears Yoshiki, Hikaru tries to pet it, but the cat hisses and bolts, clearly sensing something unnatural.

While they wander the village, a woman notices Hikaru and is stunned by his presence. Yoshiki also slowly begins to feel uneasy around him. When an old woman sees Hikaru, she screams that "Nonuki-sama" has descended from the mountain and flees in fear.

Later in The Summer Hikaru Died episode 1, Yoshiki asks the imposter directly if Hikaru is truly dead, and whether the being had killed him. The entity explains that when it found Hikaru, he was already dying. It had been wandering the mountains for a long time, void of emotions, until it encountered Hikaru in his final moments. Before it realized what was happening, it had taken his body.

As they part ways, Yoshiki asks if the being really likes him. It answers yes. Yoshiki then asks it to never leave him again.

The fake Hikaru in The Summer Hikaru Died episode 1 (Image via CygamesPictures)

That night, the old woman is seen terrified inside her home, refusing to open the door. But Hikaru’s voice comes from within, chillingly stating that he’s already inside. As she turns in horror, the scene cuts to a blood trail.

In the closing moments of The Summer Hikaru Died episode 1, police gather outside the woman’s home. She’s been found dead. Another elderly man panics, declaring that Nonuki-sama is coming for him next. A third man mentions that "Indo’s ritual" failed and asks a man named Takeda about their next move.

Takeda contacts Tanaka for help. Although Tanaka is reluctant to go to the gloomy village, he agrees, noting ominously that the locals have no idea what they’re dealing with; "that thing" is far more dangerous than they realize, and The Summer Hikaru Died episode 1 ends there on an unsettling and suspenseful note.

Final thoughts

Hikaru and Yoshiki (Image via CygamesPictures)

The Summer Hikaru Died episode 1 delivers a striking and captivating premiere, blending entertainment with a gripping supernatural horror-mystery narrative. The episode shines with its strong storytelling direction, top-tier production values, and stunning visuals.

With precise pacing and a well-structured narrative, the premiere sets a compelling tone for the rest of the Summer 2025 season, promising an emotionally rich and suspenseful journey ahead.