Ben, Gwen, and Grandpa Max next travel to Castle Bishopbrook to visit a distant relative who's royalty, but when Ben encounters a "ghost" at the haunted home, it turns out to actually be his new rival, Kevin 11, throwing even more twisted aliens his way: Thornblade, Undertow, and Dark Matter!
Plot[]
Gwen daydreams about being admired by the people of England. Max notices Gwen's accent and tells her she almost sounds as good as their cousin Wilhelmina. Ben asks who that is, and Max tells them that she's their English cousin. Max also tells them that the locals refer to her as the Queen of old haunted castle Bishopbrook. Ben freaks out hearing the word haunted, thinking that they're haunted ghost at the castle. Gwen tries to reason with Ben, but Ben runs out into the castle trying to prove himself. As Ben runs out, a shadowy figure appears watching him.
Ben runs inside the castle, noticing how he did think this through. Gwen walks in behind him disappointed in the castle, being nothing like she imagined. Wilhelmina walks out startling Ben. She greats Max and the kids. Gwen breaks out asking many questions. Eventually a gust of wind blows in, and causes a chandelier to fall. Ben transforms into Humungousaur and catches it. Ben claims that it was the work of a ghost, but Gwen says it's a logically explanation for it falling. Max offers to help Wilhelmina with cleaning the castle while the kids sneak away. She shows Max to list of things to do, Max calls for the kids, but they're gone.
Ben and Gwen walks through a dark hallway. Ben transforms into Heatblast to light up the candles in the hallway to give them sight. As soon as he lights them up, a gust of wind puts them out. Heatblast guarantees that it's a ghost, but Gwen still denies it. As Ben and Gwen walks of, the same shadowy figure from before runs by.
In another room, the two kids visits another room showing the family crest and tapestries. As Gwen examines the tapestry, a part of it begins to fold, making Ben believe that there's a ghost. He then shoots fire at it, burring it up. Ben then times out, noticing Gwen is missing. Ben gets scared and thinks about how he will save her. He visualizes different approaches with the aliens Four Arms, Overflow, and Wildvine. However both Overflow and Wildvine were missing, making Ben believe that he can't defeat the ghost without all of his aliens. Eventually a ghost-like figure arrives, with smoke beneath it. Ben runs away, and ends up cornered. The ghost reveals itself to be Gwen in a costume. Ben complains about how if he had Grey Matter, he'd see it coming. Gwen tires to cheer Ben up about having new aliens, despite the replaced aliens being inaccessible through the active playlist. Ben sees a shadowy figure run into a garden, and runs outside to get it.
As Gwen and Ben walks outside, Ben gets pulled into a bush. Ben runs through the garden trying to escape. He hears a voice telling him that there's only dead ends. Ben thinks it's a ghost. Soon he sees another figure, and runs off. He eventually bumps into it, noticing that it was Kevin. Ben questions how he got Wildvine, Kevin corrects him calling him Thornblade. Ben argues that Wildvine is supposed to be a hero, and Kevin thinks Thornblade is way cooler. Ben teases him saying he fought house plants tougher than Kevin, but Kevin begins wrapping Ben around it more vines. Ben transforms into Four Arms and punches Thornblade away. Four Arms opens a bush to find him, only to be blasted by Undertow's water. Four Arms questions how he switched from one alien to another so quickly, Kevin tells him that he doesn't need to wait.
Kevin walks away and turns into Dark Matter. Ben teases Kevin for choosing an alien as weak as Grey Matter, but then soon finds out that his Galvan form is notably taller. Dark Matter throws Four Arms around and traps him in his crystal like substance. Ben questions how Kevin got all of his missing aliens, but Kevin states that he never lost any aliens. Kevin's watch begins timing out, and Four Arms tries to stall Kevin until it does. As Dark Matter attempts to finish him off, Kevin times out. Four Arms breaks out and Kevin runs away. Ben chases after Kevin then times out. Ben demands answers from Kevin, but Kevin pushes him down to the ground, and teases him for believing that he's was a ghost. Soon they both hear a loud bear noise, scaring the both of them. Kevin jumps through a bush and trips. There the Forever Knight approaches him, offering for Kevin to join him to his cause. Kevin turns down the offer, stating that he doesn't need help from knight nerds.
Before the Tennyson's leave, Wilhelmina offers the Tennyson's gifts. She lends Gwen music box, that was handed down many generations. Before they leave Max notices that there were people ready to clean the castle, realizing that he did all of that work for no reason. The Tennyson's fly off, and Ben brags in Gwen's face that he heard a "ghost bear" noise, but Gwen pulls out her phone and pushes a button, creating a similar noise, implying that she was the one that scared Kevin and Ben.