The first episode of To Your Eternity Season 3 commences with a scene of high schoolers felling the tree roots that snaked beneath their school, unaware of the ancient power they were disrupting. Aoki, the vice president of the Occult Research/Handicrafts club, spins a tale of a legend—a powerful being who used the roots to weave a blanket of peace over the world, promising its awakening someday.
The boy, whose heart yearns for Mizuha, Hanna's friend and the club's idol, finds himself in a whirlwind of excitement as Fushi wakes up to a world he believes is finally at peace. However, his euphoria is short-lived as he is confronted by his creator, the "Black Hood," who stands over him with a rope binding him to the roots of the world. The being severs the connection, granting Fushi the freedom to reconnect with the roots at his whim.
With renewed freedom, Fushi ventures forth into the world, his eyes widening in wonder as he takes in every new sight and sound. From perching atop a building to savor the cityscape below to indulging in a cup of boba, he experiences life anew—until a truck interrupts his reverie, an obligatory rite of passage for any immortal "time traveler."
Meanwhile, Aoki discovers the next day that the roots have ceased their growth, signaling a world at peace. Inspired by this revelation, he proposes a field trip to prove their theory. Mizuha, who usually devotes her weekends to studying but believes in seizing the day, eagerly agrees to join them.
Thus begins Fushi's journey, intertwined with the lives of his friends and the mysteries of the world beneath their feet, as they all awaken to a new era of possibilities.
As she approached her front door, her gaze met her grandfather's, and she offered a warm greeting. However, her mother's impatience denied her the chance to engage in conversation. Upon returning home, the girl tried to express her desire for a moment of respite from her numerous activities; yet, her mother's eyes only seemed to scan for the next trophy or competition.
She backed away, defeated, and retreated to her room. As she gazed out at the city's nocturnal glow, her words of wanting to end it all hung in the air. Then, a slight itch began to tingle on her arm.
On Saturday, the high schoolers noticed Mizuha's probable absence and proceeded with their "mission." Aoki led them on an exploration towards the sea's edge, proclaiming that the roots they found proved their extension into the ocean. Following this, they embarked on a fishing expedition.
Meanwhile, Fushi set out to find March's whereabouts. However, upon reaching a house, he witnessed her with a family, radiating with joy. Believing she was in a favorable situation, he withdrew, his thoughts and feelings in disarray. As he turned into a fish to evade being seen, his mind was flooded with questions about the others' desires, the best way to make them happy, and whether they would ever forget about him.
While swimming as a fish, Aoki caught up with him. Fushi regained his human form, shocking the boy. The high schooler then attempted to provoke the immortal in every way possible to elicit a response. In the ensuing commotion, they both fell into the water.
Fushi rescued Aoki and pretended to be injured, luring the immortal back home. Though he knew what Aoki was doing, Fushi played along. Once inside his house, Fushi revealed his secret and transformed into the wolf. As he was fluffy and adorable, Aiko's brother begged him to stay. With nowhere else to go, Fushi accepted.
Fushi invited Eko and Horse as well, as they allowed him to have his friends there as well. However, Kazumitsu, Aoki's grandfather, perceived that having them might be dangerous. So he made them swear that it was a secret kept between them all.
Despite this, Aoki shares his discovery with his clubmates as soon as he arrives at school. As he narrates, Mizuha overhears the name "Fushi" and feels a pang of nostalgia for some inexplicable reason.
The girl returns home earlier than planned after another girl causes her to stumble and fall. As she ambles down the street, Fushi notices her and inquires if she's in pain, urging her not to neglect the injury. In that moment, he looks at her with a sense of familiarity that leaves them both pondering. And with that, the episode comes to a close.
