When the Greens try to spend an eventful day at the beach, Cricket tries to prank the beach-goers.
The Green Family is out at the beach with Bill trying to apply sunscreen to Cricket. Cricket has brought his shark fin with him and plans to prank the other beach goers with it, but Bill stops him as he wants a nice time without any trouble. Cricket tries to get confirmation from Nancy, who is all for Cricket doing his pranking, but Bill tells her to stop "making [him] the bad guy" and asks her to be responsible for once, which she reluctantly complies. In the meantime, Bill agrees to let Tilly bury him in the sand while Nancy, adorned with Bill's hat, watches over Cricket and makes sure that he does not get his shark fin back from her.
Meanwhile, Alice wanders off to get a pretzel for herself when she is attacked by a seagull for it. A nameless life guard arrives and admonishes the two from fighting and arrests them by putting them in "beach jail" for an hour while he himself eats Alice's pretzel.
Cricket is upset that he cannot prank anyone, but he comes up with a plan. He confronts Nancy and teases what he would do to prank the beach goers which ends up riling up Nancy enough that she accidentally gives him the shark fin. She keeps this information from Bill. Bill in the meantime has Tilly perfect her sand building technique and has covered up all of Bill who is now at the mercy of a crab. Cricket begins going around feeding ideas of a shark attack to the beach goers before going underwater with the fin and scaring them.
Bill finally realizes what is happening and berates Nancy who tells Bill that she cannot help being the "fun parent" and supports Cricket. The life guard hears cries of a shark and leaves Alice and the seagull unattended and they escape with the intent to get revenge.
Nancy watches as Cricket scares off everyone with his prank, but spots the life guard who has acquired a harpoon gun with the intent to kill a shark. Realizing her mistake she swims out to rescue Cricket. After unsuccessfully confronting the life guard, Alice arrives with a flock of seagulls to take their revenge on him by tossing him far away. Bill, hearing the commotion, cannot escape the sand bank, but the crab pitches Bill causing him to break free.
Nancy pulls Cricket to shore and has a self conversation; punishing herself for being careless with Cricket, much to his consternation as he promises not to do the shark prank anymore. Bill sees this and thanks Nancy. Alice and the seagulls fly off to get another pretzel while Tilly builds a Tilly-Sphinx with the sand.
Additional voices: Shane Houghton, Jeff Bennett, Tom Kenny