As a cow is about to take the first lick of a delicious ice cream cone, a fireball appears out of nowhere and melts it. He looks on in stunned silence at what produced the flame but Sonic steps in and pulls him behind the ice cream cart before leaping out himself to confront the threat. A robot with a flamethrower and dressed in garb similar to a firefighter tries to torch Sonic but can't get a bead on the speedy hedgehog. Sonic remarks that Dr. Eggman's evil fire robot is running amok, which prompts the doctor (who's sitting on a nearby bench calmly reading a magazine) to respond that he feels unjustly targeted as the only maker of evil robots. Sonic doesn't buy it and says experience taught him better.
Knuckles and Amy arrive and Knuckles brandishes a large piece of wood (along with a snappy pun) but it's incinerated out of his hands before he can use it. Amy notes the backwards nature of a fireman robot causing fires and Eggman quips that the intent should be obvious as the robot is doing the exact opposite that a firefighter would. Sticks alerts Sonic that the Evil Anti-Fire Bot is attempting to put a baby walrus into a burning house, prompting Sonic to snatch it from the robot's hands and save the helpless baby by returning it to its mother. Then Tails tells Sonic that the Evil Anti-Fire Bot is trying to put a kitten in a tree. Eggman cheers on the robot, which gets him disapproving stares from Sonic's group and Eggman admits the robot is his.
The robot continues to terrorize the townspeople and Sonic gets fed up. He jumps at the Evil Anti-Fire Bot with a spin attack and wraps it up in its flamethrower hose, causing the flamethrower tank to over-pressurize and explode, defeating the robot. Eggman exits the scene hastily while Sonic repeats Knuckles's earlier pun and gets a better reaction. Sonic asks Sticks to get the kitten back down from the tree and Sticks begins to shake the tree. Sonic protests her method but the cat eventually falls out of the tree and onto Sonic.
Back at the house the group calls a meeting to discuss Sticks's disregard for the safety of animals. Amy proposes that Sticks get a pet in order to teach the virtue of caring for an animal. Sonic agrees but then immediately disagrees to take Sticks to pick out that pet but gets dragged into it anyway. Sticks doesn't like any of the choices, saying they're too cute, fuzzy, or adorable for her taste and the pair leave. On their way back, some rustling from an overturned trash can catches Sticks's attention. Sticks digs around in the trash can and pulls out a robotic dog covered in slime. Sonic finds the thing disgusting but Sticks is enamored with it and ends up keeping it, naming it "Buster".
The group is weirded out by Sticks's strange choice of pet, given that it keeps spewing slime everywhere, but Sticks seems to ignore that and continues to dote over it. Buster's slime-producing quality starts to drive everyone nuts as it keeps interfering in everything they try to do while Sticks just blissfully ignores the annoyance. At lunch one afternoon (which is being again being ruined by Buster and his slime), a panicked voice cries out that a robbery is occurring at the Dangerco Deadly Equipment Warehouse. The doors of the warehouse are blown open and Orbot and Cubot, wearing crudely drawn Sonic and Tails masks, emerge with a squad of Buzz Bombers pilfering some robotic tentacles. Sonic's team rushes to the scene but the Buzz Bombers intercept them. Sonic tells Sticks to try to cut off Orbot and Cubot but she refuses because of Buster and takes him for a walk instead. Sonic goes after the pair himself but Buster runs up to Sonic, tripping him and allowing the two robots to escape.
The group convenes at Tails's house to lay down the law with Sticks. Sticks thinks they got together to give Buster a gift but Amy, Knuckles, and Tails all say they've had enough of Buster. Sticks says she's getting mixed messages from the team and somehow deduces that a government mind control experiment is to blame. Amy corrects her and says that Buster has got to go or Sticks won't be a part of the group anymore. Sticks says she's not going anywhere so she kicks everyone out...except they're at Tails's house. At this point Dr. Eggman drops by and offers Buster a gift as its creator; a mechanical dog bone that Sticks accepts without question.
Buster takes the bone outside and ingests it, causing him to grow to a much larger size and sprout tentacles out of its side (though not the same tentacles stolen from the warehouse job). Sonic urges the group to help him fight the transformed Buster but Sticks objects. Knuckles takes the initiative and tries to confront the robot but ends up ensnared by the tentacles. Amy and Tails soon join him, leaving only Sonic and Sticks. Sonic runs around the robot and manages to slice off one of the tentacles by using a nearby table as a makeshift projectile. However Buster regenerates the tentacle and captures Sonic, leaving Sticks by herself.
Eggman sics Buster on the only remaining target: Sticks. Sonic reminds Sticks that Buster still has a relationship with Sticks and that he won't try to attack her. Sticks tries to evoke memories of the times she shared with Buster but to no avail, which Sticks admits was because those memories never actually happened. Eggman orders Buster to finish Sonic's crew by eating them but Sticks stands up to Buster and demands he put down her friends. Buster hesitates, which leaves Eggman confused that his robot would disobey his order. Eggman and Sticks send Buster conflicting orders, ultimately resulting in Buster obeying Sticks's command and releasing her friends. Sticks then tells Buster to deal with Eggman, grabbing him by the leg and tossing him away while he regrets ever making Buster.
Sticks tells Buster to cough up the bone, which causes him to return to his original form. Later on the beach, Sticks decides to let Buster go since it is an evil robot and probably unfit to be a pet. As she waves goodbye, Tails says he found a giant octopus and wants to keep it as a pet but as soon as he does the octopus eats him and spits out his goggles. Tails reconsiders the proposition while reaching out his hand from inside the octopus.
