When Gwen drags Ben along on a hike in search of Forgeti, a yeti that makes people forget they ever saw it, Ben is dubious. With Dr. Animo on the trail of the beast as well, what looks like a hoax becomes a hero time adventure for the ages.
The episode begins with Gwen telling the story of the Forgeti. Ben, however, is tired of it. He claims that he can make better fake stuff in his sleep; Cybearg, The Bloodpecker, and the three-headed bear guard. Max on the other hand is prepared to explore the trail, and get a picture of the salamanders that live there. Tevin and Melvin both show up and tease Gwen for believing in the Forgeti.
They begin walking, and Gwen spots movement in the distance. She chases after it, and once she spots it, she believes that it's the Forgeti. However, it turns out that it was just Melvin and Tevin again. Ben transforms into Diamondhead and scares the both of them. As they both run away, Max arrives questioning what's going on. Diamondhead explains that they were making fun of Gwen for believing in "fake monsters". Gwen still denies that the Forgeti is fake, and continues to search for him. She spots a creature in the distance who she believes to be Forgeti. Diamondhead spots a pick-up truck nearby, questioning what it's doing there, and why there's animals inside. Right as Gwen attempts to touch it, it scares her. Dr. Animo steps through, greeting the Tennysons. Gwen yells at him claiming the Forgeti will stop him, but Animo laughs, amused that Gwen believes in those stories. He orders Gil to destroy them. Diamondhead easily outmatches Gil, so Animo changes his plans and captures Max. Gil brings him to the truck, and Ben's watch times out. Gwen admits that Forgeti isn't real, so she puts it all aside to help save Max. Ben transforms into Wildvine to follow them.
The two arrive at the cave, and proceeds to walk inside. Animo explains to Max that this is beyond experimentation, and the scientific method. He claims that it will be home to a new legendary creature, and the basis of the creature will be Max. Animo decides to mix Max with the salamander he admires. Meanwhile, Ben and Gwen attemps to sneak in. Ben attempts to transform into Four Arms, but Gwen states that they need a plan. So she changes the dial to Grey Matter. Grey Matter decides that their going to walk right in to take the blaster from Gil. Grey Matter manages to sneak near the cages, and he steals the laser from Gil. He forces Gil to lock himself in in the cage. Animo soon catches him, and he's holding Gwen captive. He threatens him to put the weapon down, or he'll mutate Gwen. Ben puts it down and times out. Now that Animo has found something Ben sees as worth defending, he claims that he'll never let it go again. Fog starts to form, and the Forgeti shows up. Gwen and Animo are the only two that sees it, and Animo is pushed aside by the creature. Gwen calls over to Ben, but he alongside all of the other prisoners are sleep. Gwen also begins to fall asleep.
Later on, Ben, Gwen, and Max awake in the forest. They're confused as to how they caught Animo, and how they got their. Melvin and Tevin, who were also captured, wake up laughing about their prank earlier. Gwen begins to make the observation that the Forgeti might've had some involvement. Max questions if she's still hoping to see the Forgeti, but Gwen just wants to believe a little longer. Ben jokingly says that if she believes in the Forgeti, so does he. And also the Loch Ness Monster, and Ghost. He still laughs at the thought of Forgetis existing, while Forgeti watches them from high in the trees.