In a peaceful coastal town, Ben must not only face the archaic antagonist Steam Smythe and his latest creation, the Clocktopus, but also his deepest, darkest fear: Squids!
The episode begins with Max taking Ben and Gwen to his favorite pier from his childhood, Squid City, as it could be their last chance to see it before it's replaced by a megaplex. While Gwen seems mostly indifferent, Ben's fear of squids kicks in just from seeing the squid themed décor and food all around him, causing him to change into Cannonbolt to speed off and pretend to be a vendor.
As Max questions the need to change Squid City into a megaplex, the pier is suddenly attacked by a giant steampunk octopus, intent on keeping Squid City around and preventing the production of the megaplex. While it attempts to hault the the megaplex, the sight of the Clocktopus causes Ben to have a flashback to a marine-based school play, seemingly headed by Cash and J.T., but before it can finish, Ben is pulled out of his flashback and almost hit with a giant I-bar. Coming to, Ben changes into XLR8, and charges at the Clocktopus with confidence at first, though it quickly dwindles as he dodges the tentacles.
An aperture door on the front of the Clocktopus is then opened, revealing Steam Smythe captaining it. He easily knocks XLR8 aside and then heads for civilians, destroying part of the mall's construction in front of them all. With Ben currently down, Max and Gwen throw squid trinkets at Steam Smythe, though this does not much more than annoy him and make him embrace them in a tentacle. Playing to his affinity for old fashion ways, Max and Gwen claim that Steam Smythe has offended them and they wish to challenge him to a duel, with Ben as their champion, to which Smythe agrees. A crowd then gathers to watch the duel.
Ben, however, claims he cannot fight the Clocktopus. The flashback is then picked back up, showing Ben as a member of the crew on a submarine, failing to save them from the fake squid tentacles dropped on them by Cash and J.T. Ben comments on the embarrassment from ruining the school play, clearly associating that with the squids, giving him his fear. Max, acknowledging how traumatic the day was for Ben, states that he must move on from the past, to which Steam Smythe completely disagrees with.
Ben calls off the fight and runs away, causing the crowd to leave disappointed. Once again annoyed by the antics of Gwen and Max, Smythe goes to strike them with the tentacle of the Clocktopus, however against his will it might be, only for it to be caught by Four Arms, revealing he had only called off the fight to get everyone to leave. Four Arms then runs from the Clocktopus, only to be caught by it. He once again has a flashback to the play, where Cash and J.T. are seen laughing at him for his failure in the play, causing him to proclaim he can't fight the Clocktopus.
Smythe and Max begin to tell Four Arms conflicting sides, Smythe about how much better things were in his time, and Max about how things must move forward, including Ben's fear about the play. Deciding Max is right, Four Arms breaks out of the Clocktopus' grasp, then proceeds to destroy three more of the tentacles. The two then begin to sword fight with I-bars, only for the Clocktopus to fall into the water and be destroyed, though Smythe escapes on a steampunk flight device. Four Arms changes back to Ben and then climbs onto the pier from the water, and is congratulated by Max for facing his fear.
Steam Smythe brings up his generation having built the Titanic and Hindenbergs as a way to show his generation was superior, though ironically both of which have famous disasters associated with them: The sinking of the Titanic and the crashing of the Hindenberg.