The episode begins with the boys of South Park Elementary, Stan, Kyle, Cartman, and Kenny, in the school bathroom. They are discussing the mysterious phenomenon of the "Urinal Deuce," a strange occurrence where someone has defecated in a urinal. The boys are both disgusted and intrigued by the incident, and they decide to investigate the matter further. Stan and Kyle are particularly determined to uncover the truth behind this bizarre act.

As they delve deeper into the mystery, they learn that the Urinal Deuce has become a hot topic among the students. The boys overhear various theories and rumors circulating in the school about who could be responsible for this act. The atmosphere is charged with excitement and curiosity, and the boys feel a sense of urgency to solve the case before it spirals out of control.

The investigation leads them to the school's janitor, Mr. Mackey, who seems to have some knowledge about the Urinal Deuce. However, he is unhelpful and dismissive, which frustrates the boys. They decide to take matters into their own hands and conduct their own interviews with other students. They gather a list of potential suspects, including Butters, who is known for his clumsiness and could easily be blamed for such an incident.

As the boys continue their investigation, they face various challenges, including the skepticism of their classmates and the growing tension among the students. The situation escalates when the school principal, Principal Victoria, gets involved, leading to a school-wide assembly where the Urinal Deuce is addressed publicly. The boys feel the pressure mounting as they realize that the entire school is now focused on their investigation.

In a pivotal moment, Stan and Kyle decide to confront Butters, believing he may hold the key to solving the mystery. They question him about his whereabouts during the time of the incident, but Butters is terrified and insists he had nothing to do with it. The boys begin to doubt their own investigation as they realize that the truth may be more complicated than they initially thought.

As the episode progresses, the boys uncover more clues that lead them to a shocking revelation. They discover that the Urinal Deuce is not just a random act of vandalism but is connected to a larger conspiracy involving the school's administration. The boys piece together the evidence and realize that the Urinal Deuce is a symbol of rebellion against the oppressive rules imposed by the school.

In the climax of the episode, the boys confront Principal Victoria and the school board, demanding answers about the true nature of the Urinal Deuce. The confrontation is intense, with emotions running high as the boys express their frustrations about the school's strict policies. The principal tries to downplay the situation, but the boys are relentless in their pursuit of the truth.

Ultimately, the episode concludes with the boys coming to terms with the absurdity of the situation. They realize that the Urinal Deuce, while initially a source of mystery and intrigue, is ultimately a reflection of their own struggles against authority. The boys share a moment of camaraderie as they reflect on their investigation, and the episode ends with a humorous twist that leaves the audience laughing at the ridiculousness of it all.

In the ending of "Mystery of the Urinal Deuce," the boys discover that the culprit behind the mysterious urinal incident is actually Mr. Garrison, who had been using the urinal in a way that was not intended. The boys confront him, and the truth is revealed. The episode concludes with the boys feeling a mix of relief and disgust, as they realize the absurdity of the situation.

As the episode draws to a close, the boys--Stan, Kyle, Cartman, and Kenny--are in the school bathroom, having pieced together the clues surrounding the "Urinal Deuce." They are determined to uncover the identity of the person responsible for the strange phenomenon that has been plaguing their school. The tension is palpable as they discuss their findings, each boy contributing his thoughts and theories, showcasing their distinct personalities. Stan is earnest and logical, Kyle is skeptical and analytical, Cartman is self-serving and brash, while Kenny, though muffled, adds his own unique perspective.

The scene shifts to Mr. Garrison, who is in the midst of a personal crisis. He is struggling with his identity and the implications of his actions. The boys confront him, and in a moment of revelation, Mr. Garrison admits to being the one who has been using the urinal inappropriately. The boys are shocked and disgusted, realizing that the mystery they have been so invested in was caused by an adult they trusted.

As the confrontation unfolds, Mr. Garrison's motivations are laid bare. He expresses his frustration with the school system and his own life choices, revealing a deeper layer to his character. The boys, while initially horrified, begin to understand the absurdity of the situation. They feel a mix of emotions--relief that the mystery is solved, but also a sense of betrayal and confusion about the adult figures in their lives.

The episode concludes with the boys walking away from the bathroom, their camaraderie intact but their innocence slightly tarnished. They share a moment of laughter, reflecting on the ridiculousness of the entire ordeal. Each character leaves the scene with a sense of growth, having faced a bizarre challenge that tested their friendship and understanding of the world around them.

In the final moments, the camera pans out, showing the school in the background, a symbol of the ongoing absurdities of life in South Park. The boys, now more aware of the complexities of adulthood, continue their journey together, ready to face whatever absurdities come next.

In the episode "Mystery of the Urinal Deuce," there is no post-credit scene. The episode concludes without any additional content after the credits roll. The story wraps up with the resolution of the main plot, focusing on the boys' investigation into the mysterious urinal incident at school, and the comedic elements surrounding their efforts. The lack of a post-credit scene keeps the focus on the main narrative and its humorous conclusion.

The urinal deuce is a mysterious and grotesque phenomenon that appears in the boys' bathroom at South Park Elementary. It serves as the central mystery of the episode, prompting the boys to investigate its origins. The urinal deuce symbolizes the absurdity and chaos that can arise from seemingly trivial events, reflecting the show's satirical take on how people can become obsessed with minor issues.

As Stan and Kyle delve deeper into the mystery of the urinal deuce, their friendship is tested. Stan becomes increasingly obsessed with solving the mystery, while Kyle grows frustrated with Stan's fixation. This tension highlights the strain that can occur in friendships when one person becomes consumed by a singular focus, showcasing their emotional states of frustration and determination.

Mr. Mackey, the school counselor, becomes involved when the boys bring their concerns about the urinal deuce to him. He attempts to downplay the situation, emphasizing the importance of focusing on more significant issues. His dismissive attitude adds to the comedic tension, as he represents the adult perspective that often overlooks the absurdity of children's concerns.

Cartman approaches the mystery of the urinal deuce with a self-serving attitude, using it as an opportunity to manipulate others and gain attention. Unlike Stan and Kyle, who are genuinely trying to uncover the truth, Cartman sees the situation as a chance to exploit the chaos for his own amusement, showcasing his characteristic selfishness and lack of empathy.

The other boys at South Park Elementary react with a mix of fascination and disgust to the urinal deuce. As the mystery unfolds, it becomes a topic of gossip and speculation, with various theories circulating among the students. This reaction highlights the absurdity of the situation and how quickly rumors can spread in a school environment, reflecting the emotional states of curiosity and revulsion.

"Mystery of the Urinal Deuce" from South Park's season 10 is not family-friendly and contains several potentially objectionable or upsetting scenes and aspects, including:

1. Bathroom Humor: The episode revolves around urinals and includes crude jokes and references to bodily functions that may be inappropriate for children.

2. Violence: There are scenes depicting violence, including a character being attacked, which may be distressing for sensitive viewers.

3. Mature Themes: The plot involves themes of conspiracy and deception, which may be complex or unsettling for younger audiences.

4. Language: The dialogue includes strong language and adult humor that may not be suitable for children.

5. Social Commentary: The episode satirizes serious issues, which may be confusing or upsetting for younger viewers who do not grasp the underlying messages.

Overall, the content is designed for an adult audience and may not be appropriate for children or sensitive individuals.