Lake no Himitsu-shitsu

In this adventure, we are introduced to Isamu and his father, Dr. Shigeno, a very intelligent scientist who created a revolutionary invention. However, a former research ally, Dr. Kusai, begins to pursue our protagonists, who will have to do everything they can to prevent the secret formula from falling into the wrong hands.

Source: Amazn Brasil, https://www.amazon.com.br/Sala-Secreta-do-Lago-ebook/dp/B0FV4YB7RF and Blogbbm: https://blogbbm.com/manga/a-sala-secreta-do-lago/