There are mystical items called Landtool that the ruler of Harappa Land, a land of robots, has instructed his people to find. Two of them, Robotack and Kamerock arrive in Yumegaoka and make friends with detective Kaoru Sugi and his nephew Kakeru. The two join Sugi's agency in their quest to find the Landtool and also solve crimes in their small town. At the same time, they must thwart the Gold Platinum P.D. Agency, headed by Robotack's brother and arch-enemy Torabolt, from finding and profiteering from the Landtool.
Tetsuwan Tantei Robotack provides examples of the following tropes:
- Canon Discontinuity: How Toei has treated B-Robo Kabutack and this series as of late - while the series were listed in one of the Super Hero Taihen specials, said list also included Moerro!! Robocon, which is definitely NOT a Metal Heroes series, so it was likely referring to series that had come out during the period of time that Kamen Rider was on hiatusnote ; later, Super Hero Taisen Z showed a list of the Metal Heroes series, with Kabutack and Robotack both being absent from said list; additionally, these 2 are the only series that have not received DVD re-releases.
- Crossover: The cast of Robotack meets the cast of B-Robo Kabutack in a crossover special.
- The Hero Dies: Robotack dies in the final episode. Actually not.
- Heroic Sacrifice: Robotack finally vanquishes the forces of evil in the final episode, but at the cost of his life. Or so it seemed.
- Pun-Based Title: Although Tetsuwan is an actual Japanese word, Wan is also the Japanese sound of a dog barking.
- Spoiler Title: Take a wild guess what happens in the last episode, Robotack's Death at Sea. Subverted due to Disney Death.
- Super Mode: Special Mode.