With peace throughout Ninjago, Cole and the other Ninja fell out of training and instead spent their time playing video games. After a three hour marathon, they were interrupted by Wu who unplugged the TV, who encouraged them not to put off tomorrow what could be done that day and start training again to prepare for his brother's return to Ninjago. In response Cole noted that he was going to eat a slice of pizza, but Wu knocked it out his hand before he could. After Wu pointed out that they had not tapped into the special powers of their Golden Weapons, Cole used the Scythe of Quakes to plug the TV back in.
At that moment, Nya rushed in bringing word that Garmadon was spotted in Jamanakai village. The out-of-shape Ninja then rushed out the door and down to the dragon pen where Cole mounted the Earth Dragon, though dropped the golden scythe in the rush.
Eager to get back in the action, the ninja raced each other to Jamanakai village, but upon arrival Cole argued with Zane who had arrived first. They were interrupted by the sound of evil laughter from the village and drawing their weapons, approached the village ready for battle. However,the Black Ninja was surprised to find that it was in fact Lloyd Garmadon, the dark lord's son, who was causing trouble by threatening to release the serpentine, an ancient race of snakes which once ruled Ninjago, unless they gave him candy. The Ninja tied him at the top of a sign, embarrassing him in front of the villagers as they mocked him by eating candy.
As they prepared to return to the monastery, Kai discovered the prophecy of the Green Ninja in Wu's bag which he had taken by mistake. When the other Ninja began arguing over who was to become the prophesied Ninja, Cole broke up the fight nothing that there was likely a reason Wu hadn't told them of it. Yet the question remained on everyone's mind so when they returned to the monastery, the four Spinjitzu masters challenged themselves to a tournament for the title. Cole faced off against Zane in the first round and won, and competed in the final round against Kai. However, the tournament ended when Red Ninja lost control of the Sword of Fire and the Ninja were scolded by Master Wu.
Determined to be the Green Ninja, Cole and the others devoted themselves to training. They were soon ordered back to Jamanakai Village by Wu however as Lloyd had unleashed the Hypnobrai tribe of Serpentine. This time Cole mounted his dragon without loosing the scythe and upon arriving at the village, met up with Nya. After discovering they would need the anti-venom from the General's staff to save the village, the Ninja split up. Cole went directly to the General and knocked the staff out of his hands, though while he picked it up, the Black Ninja unknowingly fell under the control of Skales. He returned to the monastery with the other Ninja to resume training, unaware he was also acting as Skales' eyes and ears on the Ninja.
It was Cole's turn to make dinner; he prepared a duck chowder, though it glued the Ninjas' mouths shut.
At one point while Cole was using the bathroom, Zane walked in and started combing his hair much to the Black Ninja's annoyance. Cole brought up the event when he and the other Ninja complained to Wu about the White Ninja's strange behavior after he unexplainably disrupted their training. As Wu explained to them how brothers can be different they were interrupted by the arrival of the Postman who had Cole's order of liver and toads for Rocky. He momentarily forgot his grievances with Zane and rushed to present his dragon with its' present.
Later that night at dinner, Cole started a food fight with the other Ninja.
The next morning, Cole and the other ninja followed Zane to Lloyd's Treehouse Fortress which he had discovered the night prior. The Ninja set out to destroy the structure but before Cole could deliver the final blow, he fell under Skales' control again and began to attack the other Ninja. Luckily, Wu soon arrived and using the Sacred Flute was able to snap Cole out of the trance. They returned to Mountain of Impossible Height only to find that the Hypnobrai had taken their staff and burned down the monastery. Cole quickly rushed to free the dragons from their pens, then blamed Zane for the destruction.
Jay's parents, Ed and Edna arrive at the ship to visit, much to Jay's annoyance. After being embarrassed multiple times by his mother, Jay ushers his parents back to their junkyard, where they are assaulted by the Fangpyre and given the venomous snake bite while the others infect vehicles in the yard to their own evil use. The next day, Jay keeps his promise to his father and visits the junkyard with the other Ninja on foot, as the Ninja's Dragons migrated east to begin a transformation in their stage of life. When they arrive, the place is quiet. He finds Ed and Edna captive and beginning their transformation to snakes. While the Fangpyre fight the Ninja, Master explains the only way to change Jay's parents back is to get the anti venom from the staff. After discovering their weapons have the ability to transform into vehicles, Jay uses his Storm Fighter plane to steal the Snake Staff from the Rattlecopter. Nya creates the anti-venom before accidentally losing the staff, and Ed fixes the "defense system" Jay was working on earlier in the episode, allowing them to take flight and escape the Fangpyre.
Cole reassures Zane in the beginning of the episode by slamming his face with a pillow causing everyone to laugh. Afterwords they begin their morning exercises, where each ninja gets excited as Zane tries to recall his dream from the previous night. To Master's riddle "What is the best way to defeat an enemy?", Cole answers Spinjitzu although it is wrong. Each ninja seems to think they are the green ninja after Zane retells his dream in detail. Cole says that because the ninja was strong enough to lift the crate off of Zane and save him, that he must be the green ninja. After the ninja infiltrate the Bad Boys Academy, Cole cuts the ropes of the students and teachers he climbs back up the chain of the anchor to reach the top of the building. Cole encounters the Anacondri and gets tripped up by dust and a rope, causing him to drop his weapon and leaving Jay to deal with Lloyd and the Anacondri.
Shortly after Lloyd joined the Ninja aboard the Destiny's Bounty, Cole decided to test his cooking skills by making a bowl of Violet Berry Soup. Unfortunately, three days of hard work were for naught; when he tasted the soup on the third day, it was barely edible. As Cole wondered what had gone wrong, Lloyd walked by and lied that he had seen Jay adding spices to the soup when Cole wasn't looking. The Black Ninja promptly tracked his blue-clad comrade down for a stern lecture, only to be accosted by Kai in turn, who accused Cole of beating all of his high scores in Fist to Face 2.
Before the argument could become too heated, Master Wu arrived and revealed that Lloyd was behind all of the pranks, which he hoped would teach the Ninja about the destructive power of rumors. Cole commented that the lesson was rather odd, and Master Wu admitted that he made it up on the spot, since his lesson book had mysteriously vanished—in fact, Lloyd had stolen it. Before anything more could be done, Nya called everyone to the bridge, where she showed her allies the pattern she detected in the locations of the Serpentine tombs. Realizing that they could now identify the locations of the remaining two tombs, Master Wu deployed the Ninja to try and stop Pythor from awakening the final tribes of Serpentine.
Cole and Zane were sent to the Mountain of a Million Steps, with the former having a laugh at his icy comrade's pink gi (courtesy of Lloyd washing it with Kai's red gi). Once they reached the foot of the mountain, Cole had Zane climb on his back, allowing him to rapidly scale the mountain without leaving the White Ninja behind. After reaching the top of the mountain, Cole and Zane entered the Constrictai Tomb, which appeared to be devoid of life. Zane discovered several drawings on the walls, and quickly translated them into an ominous prophecy about the union of the five Serpentine tribes, the four Fangblades, and the Great Devourer. Although impressed that Zane was able to translate the drawings so well, Cole realized that the prophecy boded extremely ill for them, and told Zane that they had to return to the ship and tell the others.
As Zane turned to flee, Cole suddenly sensed something moving below the ground—moments later, Constrictai General Skalidor burst from below and trapped the Black Ninja with his tail. Against Cole's orders to escape, Zane ran to his leader's defense, playing the Sacred Flute to weaken Skalidor briefly. A short battle ensued, with both ninja suffering the Serpentine General's powerful grip, but Zane eventually used the flute again, leaving Skalidor vulnerable to a knockout blow from Cole's scythe. Although relieved at their small victory, Cole quickly deduced that Pythor had been expecting them, and that their friends were likely walking into another trap.
When Cole and Zane arrived in the Toxic Bogs, their fears were confirmed—Pythor had released the Venomari tribe, using them and the Constrictai to corner Kai and Jay outside the Venomari Tomb. The situation worsened when the Anacondrai General stole the Sacred Flute from Zane, and the Ninja were forced back onto a log that began sinking into the corrosive sludge of the bog. Fortunately, the snakes were driven off by the arrival of a mysterious warrior piloting a large robot exoskeleton. The interloper proceeded to knock the Ninja unconscious with sleeping gas and fled before the Destiny's Bounty arrived to pick them up.
As the Ninja continued their training, Cole took to lifting weights in the Destiny's Bounty. Eventually, he became too strong for the heaviest available barbell to provide any challenge, forcing him to improvise—specifically, by having Jay and Nya sit on either head of the barbell while he lifted it.
Later, he watched Zane attempting to beat his old breath-holding record, sharing Kai and Jay's shock when the White Ninja remained underwater for over ten minutes. After Zane came up to the ship, the Ninja wondered if they had reached their true potential, and went to consult with Master Wu.
Although disappointed at the loss of the first Fangblade to the Serpentine, the Ninja realized that there were still three more for them to keep out of their foes' clutches. Before they could continue the hunt, however, they received a letter from Cole's father, who wanted his son to come visit him in Ninjago City. Cole was reluctant, revealing his troubled relationship with his father to his friends, and convinced them to act as though they had been at the dance school all this time.
When the Ninja went to visit Lou, they were asked to demonstrate their dancing skills, with little success. However, Cole noticed that the Blade Cup—awarded to the winners of the annual "Ninjago Talent" show—contained another Fangblade, and resolved to enter the competition so that they could get it before the Serpentine did. However, unconvinced that their attempt at dancing would be good enough, he told the others that they would have to steal it during the show. Unfortunately, Lou overheard the plan, and angrily confronted his son about their planned deception before storming off.
Lou's words had a deep impact on Cole, and he changed his mind when the team was next to perform in the talent show—the Ninja were going to win the Blade Cup fair and square. Instead of the planned dance routine, the Ninja donned their suits and performed Spinjitzu for the crowd, fending off a Serpentine attack mid-performance. At the end of their show, Cole defeated three Fangpyre by performing the legendary Triple Tiger Sashay, earning them a perfect score from the judges (despite a disguised Pythor's attempt to underscore them).
Although pleased by his team's success, Cole was saddened to see no sign of his father in the crowd. When the Ninja went backstage with their prize, however, Lou appeared and congratulated his son, admitting that he now saw that Cole had a greater destiny than following in the footsteps of the Royal Blacksmiths. Unfortunately, the reconciliation was ruined when Pythor had this minions drop stage equipment on Lou—while Cole dived to protect his father, the Serpentine stole the Blade Cup and fled. The other Ninja lingered to check on Cole, only for the Black Ninja to emerge unharmed, having unlocked his True Potential after mending his relationship with Lou.
In the aftermath of the attack, Cole and his friends returned to Lou's house. They lamented the loss of another Fangblade to Pythor, but the defeat was tempered by Lou, who showed them a picture he had taken of them with the Blade Cup. Along with the rest of his team, Cole happily hugged Lou, who welcomed all four Ninja as part of his extended family.
When Serpentine activity became surprisingly infrequent, Cole joined the Ninja in cornering a lone Venomari Soldier in the alleyways of Ninjago City. The Soldier revealed that Pythor was on the trail of the final Fangblade, halfway across the world, and the Ninja realized that they had no chance of claiming it from their foe.
Back on the Destiny's Bounty, Lloyd suggested stealing the other three Fangblades back from the Serpentine, and Nya discovered their new lair underground. In preparation for the important mission, the Ninja began training to counter the Serpentine's unique abilities, with Cole having Master Wu trap him in a net so he could learn how to escape the grip of the Constrictai. When the ship arrived at the Mountain of a Million Steps, the Ninja, Nya, and Master Wu entered the Constrictai Tomb without any sign of the snakes visible, only for Cole to inadvertently open the path to the fortress by touching a crude drawing of the Ninja on the walls.
Despite an attempt to sneak in unnoticed, the Ninja were quickly spotted and forced to fight their way to the Fangblades. Cole found himself trapped by Skalidor's tail, but relaxed his body to escape the coils and retaliate with a Triple Tiger Sashay. Eventually, the Ninja reached the bottom of the fortress, and Cole rushed forward to grab the Fangblades, but his approach triggered another trap that left him and his allies in a cage. To add insult to injury, Pythor returned at that moment, the fourth and final Fangblade in his grasp.
Trapped and disarmed, the Ninja could only turn to Lloyd for help, contacting him through the Samurai Mech's communicator. When Lloyd said that he was coming to help them, Master Wu told him not to risk it, but Cole pointed out that the whole world was doomed if Pythor successfully revived the Great Devourer. As the Serpentine began a night of Slither Pit battles to celebrate their imminent victory, Cole attempted to pass the time by playing checkers with Jay, only for Kai to steal the latter's hair oil as part of an escape plan. After Kai slipped out of the cage and climbed onto a hanging chain, Cole led his friends in running back and forth in the cage, aiding Kai's swinging motions. Unfortunately, Pythor saw the attempted escape and had the heroes restrained even further, with Cole sarcastically commenting on how much better their position was now.
Cole watched as Lloyd made his entrance and attempted to intimidate the Serpentine, and bore witness to the arrival of Lord Garmadon and the Skulkin. In the resulting fight, Pythor pulled a lever that caused the Ninja's cage to begin moving—moving, Cole noted, towards the acid at the bottom of the fortress. As the Ninja climbed up on the bars to avoid the corrosive goo, Lloyd freed them from their prison, allowing them to grab their weapons and rejoin the battle. During the fight, Pythor bumped into Cole, dropping the Fangblades. Cole immediately challenged the Anacondrai to battle, but Pythor simply vanished before his eyes. Deciding to take what they could get, the Ninja grabbed the Fangblades and ran back to their ship.
With all four Fangblades in their possession, the Ninja threw an impromptu party, with Cole making fruit punch for his friends. When Lloyd arrived to report that his father had left, Cole joined the others in toasting Lord Garmadon, unaware that Pythor had stowed.away on the Destiny's Bounty during the battle.
At the beginning of the episode, the ninja and Nya are on their way to Torchfire Mountain to destroy the Fangblades. As Kai and Nya are talking about it, Cole bursts in, looking rather ill from the ship's swaying—after Jay has a laugh at his expense, talk turns to Lloyd and how no one expected him to be the Green Ninja. Later on, the ninja are on the deck as the storm has passed. Kai, Jay, Cole, and Zane meet Master Wu on the deck with the Fangblades. Zane notes that Master Wu is rather melancholy, prompting him to tell the ninja about his destiny, saying that he "will not be able to see tomorrow." The ninja do not understand, but proceed to set up a plank from where they can throw the Fangblades into the volcano. Unfortunately, Pythor chooses that moment to sabotage the engines, jerking the ship to one side and throwing Master Wu over the edge.
After witnessing Master Wu be consumed by The Great Devourer, Cole, along with his friends, set out on the Destiny's Bounty, until it was destroyed. He was later part of the plan to trap The Great Devourer, and gave Lord Garmadon his Golden Weapon, expecting it back. It was stolen afterwards.