When Venice starts becoming a pollution- and rat-ridden Ghost City, Gaia sends the Planeteers to investigate, suspecting Verminous Skumm is up to his old tricks. Sure enough, the team's rodent-like nemesis has another scheme up his sleeve: infecting rats with specially-treated cheese so that their bites will sicken and kill humans.
This episode includes examples of the following tropes:
- Almost Dead Guy: Downplayed. Ma-Ti, very sick after being bitten by one of Skumm's rats, manages to use his Heart power just long enough to give Risa an idea how to fix the problem. After delivering the message, he falls unconscious again, but the proposed antidote keeps him and the other victims from actually dying.
- Bridal Carry: A platonic, male-on-male example; Ma-Ti crumples to the ground after being bitten by one of Skumm's mutated rats. Wheeler lifts him princess-style so that they can get him to the hospital.
- Catch Phrase Interruptus: A variant; after deciding that they need to combine their powers, Kwame pauses a moment before saying "Earth" to let Wheeler rouse Ma-Ti. Ma-Ti struggles to bring himself around and then loses consciousness, making it impossible to complete the calling sequence.
- Coincidental Dodge: An infected rat was about to bite Wheeler's hand, but then he picks up the boat oar, unknowingly knocking the rat back.
- Crisis Catch And Carry: Played with; when Ma-Ti collapses after being bitten by a mutated rat, Wheeler picks him up to carry him to the hospital, which is when Skumm sics a horde of rats on them. Wheeler continues carrying Ma-Ti throughout the escape, up until they reach the relative safety of the catacombs and he needs to use his ring to light up the passages. He hands his "little buddy" off to Kwame, who carries Ma-Ti the rest of the way.
- Damsel in Distress: Local pathologist Risa Fellini ventures into a quarantined area to catch a rat to study and the rats soon corner her. Fortunately for her, Wheeler and Linka hear the noise and come to the rescue.
- Died in Your Arms Tonight: Downplayed. After Ma-Ti collapses from rat-bite illness, Wheeler gathers him into his arms for the trip to the hospital. Ma-Ti remains awake, if too weak to do or say much, for most of the trip. Then Skumm's forces almost overrun the group, and Wheeler, at Kwame's urging, tries to rouse Ma-Ti so they can call in Captain Planet. Ma-Ti struggles but can't manage it, slumping unconscious against his teammate's chest.
- Everyone Laughs Ending: The last scene before the Planeteer Alert has the team and two of the locals discussing having lunch. One of the locals, Pietre, makes a joke about not wanting cheese (which played a big role in the episode's conflict). Everyone laughs rather than being upset about the reminder.
- Find the Cure!: This is what Risa, as a pathologist, has been trying to do from the start – and it becomes even more important for her after her young relative/friend/assistant, Pietre, gets infected. She succeeds thanks to Ma-Ti (infected himself) giving her a tip about a tropical plant with anti-toxic properties.
- Immediate Self-Contradiction: Skumm complains that Captain Planet showing up is the worst thing that could possibly happen... only to contradict himself seconds later when he notices that the Captain redirected the torpedoes he shot into the canals so that they're coming back at Skumm's lair.
- Inadvertent Entrance Cue: After Risa manages to cure Ma-Ti, Wheeler says that now they can deal with Skumm and his rats. Immediately afterwards, a nurse races in, yelling about the hospital basement being infested.Wheeler: At least we don't have to go too far.
- Instant Illness: The rats' bites take effect pretty quickly; Pietre starts moaning and loses consciousness on his feet within minutes of being bitten. When Ma-Ti is bitten by a rat infected by a "fast-acting" mutating formula, he collapses to the floor, unable to stand and crying out in pain within moments. Before the team can reach the hospital, he's unconscious and already in an advanced stage.
- It's Personal:
- Local pathologist Risa Fellini was already doing everything she could to find a cure (down to sneaking into quarantined areas to catch an infected rat), and then her young relative/friend/assistant Pietre gets bitten, making her drive to solve the mysterious problem very personal.
- The Planeteers are initially in Venice only because thwarting Skumm and other villains is what they do, but then Ma-Ti gets bitten and becomes seriously ill very quickly.
- Mundane Solution: The Planeteers are covered in polluted water, keeping their rings from working. They then come across a hose linked to clean water and Gi tries to use her ring on it, but it doesn't work. She wonders how they can turn on the water, until Ma-Ti simply turns the valve to the water supply, embarrassing her.
- Not Quite Saved Enough: Hearing Risa scream as the rats attack her and Pietre, Wheeler and Linka move in to chase them off. However, just as it looks like things are under control, Pietre starts moaning in pain and says that one of the rats bit him, meaning he's infected with the mysterious plague.
- Old-Fashioned Rowboat Date: Played With; when Gi suggests they split up to find clues, Wheeler and Linka take a gondola. For the first part, it's fairly ordinary; Linka is sitting in the boat and Wheeler is paddling as they discuss the situation. However, Linka admits that Venice would be fairly romantic if not for the current problem. They're getting mildly flirty when a mutated rat shows up and interrupts things.
- Plague Episode: Subverted; the mutated rats' bites make anyone bitten seriously ill, and for most of the episode, the Planeteers and the medical professionals alike think that it's some kind of plague. However, it turns out that the bites introduce polluted canal water rather than a virus into the wound.
- Polka-Dot Disease: A variant; the mutating formula causes the affected rats to develop yellow splotches. When one bites Ma-Ti, he breaks out in similar splotches within a few minutes.
- Ship Tease: While she and Wheeler are investigating Venice in a gondola, Linka admits that the city would be a romantic place if not for the problem of the week. He puts a hand on her shoulder and she turns her head to smile at him, only for a mutated rat to interrupt the moment. After they knock the rat off the gondola, she seems interested in picking up where they left off rather than pretending it didn't happen.
- Suicidal Lemmings: By the end, the mutated rats have been driven so crazy that they swim out to sea, conveniently preventing them from spreading the "plague" any further.
- Trauma Button Ending: Played with. The episode consists of Skumm trying to ruin Venice with plague rats he infected with treated cheese. At the end, Wheeler asks one of the locals if he wants to join them for lunch; the boy quips that he's fine with it as long as it isn't grilled cheese. Everyone knows that he's claiming aversion because of the just-solved problem, but they find the comment amusing rather than triggering.
- You Dirty Rat!: Played With; Skumm, as always, plays into the negative stereotypes about rats and his swarms of mutated rats are a major threat. However, non-mutated rats are presented as regular animals; during one scene, Ma-Ti finds two cowering in an unlit fireplace and uses his ring to calm them.
- Zerg Rush: The mutated rats attack in a huge swarm. Even when Wheeler blocks them off with a wall of fire, the larger rats still jump through the fire with no concern for injury, prompting Wheeler to call them crazy.
