After a curious young student named Jason meets Isobel - a mysterious transfer student who joins his class, Jason discovers the existence of talking miniature cars called Mecardimals. Isobel tries to keep them a secret but is surprised to learn that Jason has already befriended his own Mecardimal, who seems to be on a mission.
Jason starts finding other Mecanimals to help him battle.The clash of Blue Land versus Red Hall continues as F1 Shuma and Alta battle. Isobel must win in her quest to seal all the Mecanimals or else Ryan will use them to rebuild his world.
With Tanatos offering to battle beside her, Dana is rallying to get her brother back. Her new allies don't think she's strong enough yet to defeat Black Reef. What will Dana do if they're right?
Geryon's evil influence over Dana is really taking hold. She's completely forgotten who she is. Dabi learns he was under the same evil spell and vows to snap his sister out of it.
Sphinx reveals it was Eltopo, not Mr K, who created him. Dr Franklin confides in Isobel that he thinks Eltopo is Mr K, not realizing Jason is listening to their conversation.
Jason and his friends head through the valley to avoid Mecanimal Mantari's radar. Back at Black Mirror's hideout, Eltopo has been locked away because Sphinx escaped. Now left to find Jason alone, Vandyne is even more frustrated.
While Juliette, Brandon and Kevin are playing games, Brandon wonders if it's raining in Jason's world too. This sparks a memory from Juliette. She says that Jason left a letter in a book he'd borrowed from her.
Black Mirror's hideout is located on the other side of the ocean. Jason, Isobel, Ryan and Team Goblin are looking for ways to get to Dark Island, the home of Black Mirror and Lord Eltopo.
Vandyne and his jumbo Mechanimal, Ex, duel against Isobel, Ryan and Dabi. No matter what the trio do, they can't seem to beat Vandyne. Jason can't find Mr. K after they decide to run from Black Mirror and Vandyne is on the hunt for Mr. K.
Black Mirror's highest officer, Jealousia, appears out of nowhere. She's been sent by Black Mirror to regain control over Vandyne. His disbelief in who she is does not go down well with her.
Jason and Mr. K hesitate to return home, since they feel responsible for what Black Mirror is doing. They decide to finish off Black Mirror, and split up to find the jumbo Mecanimals.
Jason, Mr. K, Ryan and Isobel continue their quest for the last two jumbo Mecanimals. Vandyne has tamed Ex. Ryan has mixed feelings about Jason's presence. A search for Titan finds Ryan and Urus battling with Vandyne.
Jason's last day in Tri Force arrives. Ryan's early start to the day could help him find the last jumbo Mecanimal, Yota. Isobel wants to send Jason home but the dimension transport machine has been blocked by Black Mirror.
Jason, Mr. K and Isobel find their way back to Earth, surprising Jason's mom. Jason's thoughts are still with Tri Force. Isobel tries to console him and remind him of the benefits of being back home
On Dark Island, Ryan and Team Goblin head for the teleport path. Vandyne is so sure Jason will return to Tri Force, he needs him to so he can beat him in battle.
Jason's return to Tri Force fills Ryan and Isobel with joy. They plan to take him on a tour of Blue Land and Red Hall, but must first defeat Black Mirror. Vandyne comes to challenge Jason to battle, but winds up fighting with Isobel.
Ryan firmly believes that he would never be brainwashed with his strong mind. Jealousia and Isobel appear in front of Jason and Ryan, thus the battle begins. Jason and Ryan tries to wake Isobel up, but it doesn't work.
Jealousia wants to brainwash Jason but is prevented by Vandyne, who wants Jason himself to create his own downfall. Ryan and Isobel take on Team Goblin.