Dragonaut: The Resonance

Jin Kamishina, an 18-year-old survivor of a shuttle accident that killed his family, lives in isolation while avoiding questions about the incident. As Earth faces a potential asteroid threat and the ISDA initiates the "D-Project," Jin encounters a mysterious creature that attacks him, only to be saved by a girl named Toa who can fight it off.

Jin awakens in an ISDA facility and is interrogated about a shuttle accident from two years prior, during which he learns about the asteroid Thanatos and the extraterrestrial beings known as Dragons. After discovering that a Dragon was responsible for the accident, Jin demands that the truth be revealed to clear his father's name, but instead is offered the chance to become a Dragonaut, which he refuses. He later reconnects with his childhood friend Kazuki Tachibana, who works for the ISDA, and meets Toa, with whom he had planned to reunite. Their reunion is interrupted when the ISDA tries to capture Toa, and a rogue agent transforms into a Dragon to attack Jin, prompting Toa to reveal her own ability to transform into a Dragon to protect him.

Toa and Spirytus engage in a fierce dragon battle, prompting the ISDA to intervene by sending Machina, Amadeus, and Howlingstar—controlled by Akira, Sieglinde, and Raina. As Toa holds her own, Gio, Kazuki's dragon, arrives after being awakened by Toa's shock wave, and Jin joins the fight by riding Gio. Just as Toa and Gio are about to connect, Howlingstar attacks, leading to a clash that results in Gio and Jin falling into the ocean.

At an ISDA meeting, the potential disclosure of the D-Project is discussed. Jin awakens on a beach with Gio, and after hearing Toa's song from the moon, the two are captured and taken back to ISDA. During questioning, it is revealed that Jin and Gio orchestrated their capture to obtain a space pod, which Jin attaches to Gio's neck before they head toward the moon in search of Toa.

A flashback reveals the failed military Resonance program from five years prior. Currently, Gio abandons Jin during their search for Toa, unaware they have nearly found her, while the ISDA discloses the truth about the D-Project and Thanatos. The Dragonaut team shifts focus to the D-Project, and Jin is captured by Garnet and the military on the moon. A dragon-specific broadcast lures Gio, who, after seeing Toa in a video, rescues Jin and transforms into a dragon during a battle with Garnet.

A flashback reveals that Jin was operated on after the shuttle accident, during which Yuuri, an ISDA researcher, observed possible signs of a Resonance. In the present, Yuuri and Sakaki request that Kiril reassign the Lindworm Unit to capture Toa, leading Raina, Akira, and Sieglinde to travel to the Moon, where Jin and Gio continue their search. Meanwhile, Yuuri encounters Kō with evidence against Amagi, and Toa, encouraged by a coffee shop owner, decides to find Jin, only to be confronted by Howlingstar, Amadeus, and Machina.

Jin, Gio, and Toa reunite and are given a spa resort visit by a coffee shop owner, where Jin and Toa grow closer and Gio contemplates his role and connection to Toa. Meanwhile, the Lindworm Unit, excluding Raina who meets with Garnet, also arrives at the resort. After a confrontation, a battle ensues that damages the pool and separates the groups through underground waterways. Jin and Sieglinde are reunited, and with the help of shared memories, she begins to warm to him. Gio later finds them, having joined forces with others to locate Toa. As the groups come back together, Jin, Toa, and Gio escape, with Sieglinde allowing them to leave. Meanwhile, Kazuki meets Widow again on Earth.

Jin, Toa, and Gio escape from a spa resort and attempt to decide their next move. Jin wants to start a quiet life on Earth, but Toa leaves them during the night to complete her mission. As Jin searches for her, Kazuki and Widow intervene, capturing Gio, while Toa turns herself in to Raina. With help from Kazuki, Jin tries to retrieve Toa, and eventually, Gio comes to understand that he has been separating Jin and Toa.

Jin learns that Toa was responsible for the shuttle explosion that killed his wife and daughter two years earlier just as the Lindworm Unit attacks him, Gio, and Toa. Meanwhile, Garnet and the military discover that the Resonance data provided by Raina is fake, prompting her to attack the shuttle. As Gillard forces close in, the trio is saved by a fourth dragon from the Vritra Unit, but the military continues its assault. With enemies boarding the shuttle, Gio reminds Jin of his duty to protect Toa, leading to a successful counterattack.

At an ISDA meeting, the team discusses Kazuki's role as a Dragonaut and the status of the Album, Jin, Gio, and Widow, who are currently held in a containment facility. Meanwhile, Jin learns about the Resonance process from Yuuri, who reveals he resonated with Toa two years earlier. Elsewhere, Garnet attempts to apologize to Prince Asim, who has shifted his focus to obtaining Toa. During a transport of Toa, the ISDA is attacked by the Gillard military, while Akira and Machina manage to free Jin after a confrontation with Laina and Howlingstar.

Jin, Akira, and Machina take shelter in an abandoned house after escaping, believing they are no longer pursued by the Lindworm Unit. Meanwhile, Toa is captured by the Gillard military and taken to Mars, where Prince Asim shows more interest in her true form than in her warnings. As Yuuri swims to Tartarus to alert the ISDA about Toa's capture, a new threat emerges when a fourth dragon from Thanatos attacks Earth, destroying most of the ISDA's Vritra Unit before Machina recognizes it.

The fourth dragon, Ostrum, causes widespread destruction on Earth before vanishing, leaving the ISDA unable to respond. It later reappears and overwhelms the Lindworm Unit in battle, prompting Akira to intervene with Machina. Meanwhile, Jin is taken to Tartarus by Kō, where he encounters Kazuki's claim over Gio, while at the ISDA base, Kasuga is confronted by Yuuri and involved in a critical incident involving the dragon sample. Ostrum, having evaded the Lindworm Unit, contacts Kasuga in Communicator form, questioning his allegiance to humanity. On Tartarus, Gio transforms into his dragon form and departs with Jin.

A flashback reveals the origins of the D-Project a decade earlier. In the present, Ostrum and Atrum continue their battle, and Kasuga explains his reasons for protecting humans. Meanwhile on Mars, Toa attempts to convince Asim to let her revert to her true form to escape, but fails; later, Nanami tries to free Toa to save Earth but is shot by Garnet. As Jin and Gio head to Mars, the Lindworm and Vritra Units attempt to destroy Ostrum with a Type-X warhead.

In a flashback, Raina is revealed to have known Jin's father. In the present, Raina and Howlingstar visit Jin and Gio, with Raina offering Jin the chance to become a Dragonaut, though he initially refuses. Meanwhile, Kasuga shares his backstory with Yuuri, and Akira speaks with Sieglinde before an ISDA broadcast interrupts. Later, Jin, a revived Gio, Akira, and Machina prepare to travel to Mars, but their mission is jeopardized when Kazuki attacks them aboard the Widow, causing damage to ISDA facilities before an explosion destroys the ship and Kazuki. The team continues their journey to space as a mysterious creature awakens on Thanatos.

A flashback reveals that Asim, as a teenager, had a connection with a dragon egg. In the present, Garnet unleashes her full power and injures Gio, who escapes to an abandoned facility with the others and is healed by Toa. The group discovers an underground hot spring, where relationships develop and tensions rise, leading to a ceremony for Jin and Toa that is violently interrupted by Asim, resulting in Akira's death and triggering Machina's uncontrollable rage.

A flashback reveals how Asim earned his title twelve years prior. In the present, Asim and Toa debate humanity's nature, interrupted by Jin's arrival. Jin and Gio confront Asim and Garnet, leading to a battle that culminates in Toa and Jin reuniting.

The Lindworm Unit travels to Mars after Machina goes out of control. There, Kō demands that the Gillard King relieve Asim of his command, while Garnet transforms into a dragon and subdues Machina. Gio, with Toa and Jin, defeats Asim's fleet, and a battle ensues between Gio and Garnet, with Machina briefly joining before being repelled. After Gio is struck by an attack intended for Toa, he unleashes a powerful explosion that engulfs Asim and Garnet, and Howlingstar rescues Toa and Jin. In the end, Machina traps herself and Akira in ice.

A year after the ISDA comes under Gillard control, the Dragonauts are scattered and pursued as the Gillard King and Sakaki view all dragons as threats, except those under their authority. A new D-Project emerges as Jin, Gio, and Toa live in seclusion until Sieglinde and Kō arrive to address the ISDA's stance. Toa suggests that Thanatos would abandon Earth if it recovered its dragon eggs, and later, she and all dragons sense a change from Thanatos after expressing her feelings for Jin.

Jin, Toa, and Gio are forced to flee after their home is destroyed by Agathions sent by the ISDA, and they take refuge at the Baumgard estate with Sieglinde and her father, Wilhelm. Meanwhile, the ISDA continues its research on dragons to combat Thanatos, discovering that artificial dragons have developed an immunity to their anti-Thanatos experiments, but the treatment might still be effective on original dragons. As the group prepares to leave, Wilhelm offers to keep Sieglinde, but she chooses to leave with her companions.

Jin and his group continue their journey when Gio mysteriously vanishes after sensing a threat from Thanatos. Upon reaching the ocean, they encounter a submarine piloted by Yuuri and Kasuga, who invites them aboard. As plans are made to attack Tartarus, battles and infiltration missions unfold, leading to the discovery of Raina and Itsuki at an ISDA base and the revelation of Sakaki's plan to use the "Aegis" on captured dragons. Meanwhile, Laura appears and fights Kasuga, while others work to free the dragons and reunite with allies. Just as Laura escapes, Gio unexpectedly returns and attacks his own comrades.

Gio targets his former allies, incapacitating them one by one and warning Jin that Toa is in danger. After Toa refuses his offer to join him, Gio reveals he has become Thanatos's successor. Laura, who attacks Gio and is also knocked out, is later revealed to be the last original dragon from Thanatos, and as Toa heals her, Sakaki and Jin discuss their next steps while evading soldiers.

Sieglinde and her allies take shelter in an abandoned building on an island, where they discover Sakaki, who has washed ashore. Meanwhile, Kazuki and Widow discuss Laura's condition as she is experimented on by the ISDA, and Kasuga reveals to Yuuri the original purpose of the dragons sent to Thanatos. As tensions rise, Jin and his team confront Sakaki, and later attempt to defend Kasuga from an attack by Gio, with Kazuki and Widow arriving too late to prevent Widow from being damaged. As Thanatos draws near, Machina and Akira are shown to vanish from their ice tomb.

Gio urges Jin to relinquish Toa and departs toward Thanatos, where the Gillard fleet engages in battle but is defeated. As Jin spends time with Toa and others consider leaving for space, Gio interacts with Machina and Akira, who have become part of Thanatos's soul. After Jin allows Gio to take Toa, he encounters a grieving Kazuki, and they reconcile before storming the ISDA with Sakaki's help, who is wounded as he sends Jin and Kazuki away. Laura protects Sakaki, who dies in her arms, allowing Kasuga to absorb the anti-Thanatos factor.

Sieglinde and Raina use the Aegis system to fire a beam at Thanatos, causing the Dragonaut team to be transported inside, where Akira and Machina explain Thanatos' true nature. While most of the team decides to leave, Jin is taken to Toa by Gio, who attempts to kill him to merge with Thanatos through her. As Toa and Jin reunite, Thanatos, observing their bond, decides to fuse with humanity rather than destroy it, and Jin, Toa, and Gio exit as Thanatos begins the process.

The Dragonaut team works to save humans from billions of Ostrums unleashed by Thanatos, while Toa, Jin, and Gio attempt to confront Thanatos directly. With Kasuga's sacrifice clearing their path, the group faces the original Ostrum and other challenges, ultimately leading to the deactivation of all Ostrums and the resolution of Toa's stigmata. The episode concludes with Gio departing for space and Jin and Toa beginning a new life together.