Guren and Ceylan track down and meet Chooki and Toxsa, the two other Earth boys who possess cores and become Tenkai Knights on Quatron! Their friendship gets off to a bumpy start.
Guren and Ceylan discover two other human heroes who have 'cores' and who can also travel to Quarton, but they don't know who they are or where they come from.
Guren Nash gets settled into his new town and meets Ceylan. The two become fast friends and their life takes an unexpected and adventurous turn when they receive mysterious small 'cores' that they can hold in their hands and uncover a hidden portal.
The boys are starting come together as a team as they learn more about Quarton. While on Quarton - in search of the next Dragon cube - the boys discover that they can combine their Tenkai Knights to become something more powerful, the Prodojet. Back on Earth, the guys learn that someone stole the Key from the museum, possibly for Vilius.
As the four heroes gain confidence after having gain another cube of the Tenkai Dragon, Vilius decides to make his epic presence felt. The Guardian warns the four about the danger of being over-confident, but the boys aren't really listening.
The boys asked Mr. White who manages the Earth side of the portal, an intriguing thrift store, for some Quarton help, but he says he'll only help them if they agree to help him in the store. Believing in Mr. White's procedure, Guren unlonks his Titan Mode for the first time.
A mysterious new student arrives in Brandom City while on Quarton, Tributon fights to achieve Tenkai Titan mode. In the end, the Tenkai Knights face the appearance of Dromus, an evil clone of Bravenwolf who takes the fourth Dragon Cube with him.
Chooki has always been good at sports, school, and, well, everything. But in order to save Toxsa, Chooki gets himself jinxed and becomes clumsy and unable to do what he's best at. The four travel back to Quarton, where Chooki unlocks his Titan Mode while overcoming the jinx.
Commander Beag sacrificies himself the save the Tenkai Knights from falling down, causing them to develop a new Robofusion. They soon find out Beag is trapped in the Valley of Secrets and go to rescue him. They also find the fifth and last Dragon Cube inside the Valley.
Jealous of his teammates all being able to achieve Titan Mode, Toxsa travels to Quarton to train in secret. Meanwhile, Vilius sends out an attack, and Toxsa is captured. The other Tenkai knights travel to Quarton to save Toxsa. After realizing he needs his friends, He goes Titan and forces Vilius' forces to retreat.
On Earth, Guren receives Gen's advice about "choosing the side he wants". Meanwhile, the Corekai decide to infiltrate into the Dark Fortress to find the last Dragon Cube. But Dromus is equipped with a Core Corrupter to make the Corekai evil. Remebering Gen's advice, the Knights are able to turn their allies back to their old selves, causing Dromus to retreat. The heroes finally get all Dragon Cubes. Back on Earth, Guren's computer recives a meesage telling he is one of the "keys" that awake the Tenkai Dragon.
The gang splits into two groups, Guren and Chooki try to find a clew about the White Dragon Key. They find a sign which takes them to another and another (at one of these signs they spot Gen). They finally arrive at the Key and have to go through booby traps. Guren finally gets through and takes the key. Meanwhile Toxsa and Ceylan are fighting such a hard battle they have to go Titan mode. They seem to be holding the Corrupted off but more keep coming. Suddenly Dromus shows up in the end and says that everything is going according to his plan.
Following the battle located in the Dragon's Nest, Guren and Chooki travel to Quarton with Boreas the five Cubes are combined into one giant cube that can be only opened with the Dragon Key, awakening the Tenkai Dragon. However, Dromus captures it in a trap and transports it to the Corrupted headquarters. During the fight, Guren reveals his human identity to Vilius before destroying him. In the aftermath, Vilius revives and swears to conquer Quarton and Earth.
Vilius has kidnapped the Tenkai Dragon and Guren tires to figure out their next move. On Earth, a stranger returns to Benham City.
Beni and Gen scheme on Earth for a way to distract Guren from the other boys. On Quarton, a new villain named Venetta is revealed.
Ceylan's self-doubt leads him to wonder what skills he brings to the team. Is he the best Tenkai Knight he can be?
On Earth, Mr. White takes the boys fishing. Everybody catches a fish but Chooki. He takes this pretty bad, and wants to keep trying until he catches one. Meanwhile, on Quarton, Vilius and the Corrupted can finally withdraw the Tenkai Dragon's energy. Granox, Slyger, a robo-beast, and a Corrupted soldier can robofuse as well. Also, Boreas and the other guardians mention that the balance of tenkai energy is unbalanced.
Venetta and Dromus appear to have a falling out, later Beni reveals her identity as Venetta to Guren and the others. Meanwhile, Boreas and the other Guardians engage Vilius and the Corrupted in a battle to protect the portal to Earth.
Guren and the others learn that the Black Dragon Key is hidden inside the building were his father works. As the group decides to look inside, Chooki still has doubts that Beni wont betray them.