"Wanpaku Tanteidan" centers on a group of young detectives who solve mysteries in their small town. The protagonist, Kenichi, leads the group, which includes his friends and classmates. Each member brings unique skills and perspectives, contributing to their collective problem-solving abilities. The series is episodic, with each episode presenting a new mystery, ranging from missing items to unexplained phenomena. The children use their curiosity, resourcefulness, and teamwork to uncover the truth behind these incidents.

The narrative often blends lighthearted humor with moments of suspense, creating a balance that appeals to younger audiences. The mysteries are typically grounded in everyday scenarios, making them relatable while still engaging. The characters' interactions and dynamics are central to the story, with their friendships and rivalries adding depth to the plot. Kenichi, as the leader, often takes charge, but the group's collaborative efforts are emphasized, showcasing the importance of teamwork.

Supporting characters, including family members, teachers, and townspeople, play roles in the mysteries, sometimes as suspects or sources of information. The series occasionally introduces recurring antagonists or rivals who challenge the group, adding variety to the episodic structure. While the tone is generally light, certain episodes explore themes of trust, responsibility, and perseverance, providing subtle moral lessons without overt didacticism.

The setting is a quaint, fictional town that serves as a backdrop for the children's adventures. Its familiar, everyday environment contrasts with the intrigue of the mysteries, highlighting the idea that curiosity and observation can uncover hidden truths in ordinary life. The series maintains a consistent pace, with each episode resolving its central mystery by the end, ensuring a satisfying narrative structure for its target audience.