thumb|left|upright|Jo, Zette and Jocko in Cœurs Vaillants Hergé's next Tintin story, The Broken Ear (1935–1937), was the first for which the plot synopsis had been outlined from the start, being a detective story that took Tintin to South America. It introduced the character of General Alcazar, and also saw Hergé introduce the first fictional countries into the series, San Theodoros and Nuevo Rico, two republics based largely on Bolivia and Paraguay. The violent elements within The Broken Ear upset the publishers of Cœurs Vaillants, who asked Hergé to create a more child-appropriate story for them. The result was The Adventures of Jo, Zette, and Jocko, a series about a young brother and sister, plus their pet monkey and the parents. The series began with The Secret Ray, which was serialised in Cœurs Vaillants and then Le Petit Vingtième, and continued with The Stratoship H-22 and finally The Valley of the Cobras. Hergé nevertheless disliked the series, commenting that the characters "bored me terribly." Now writing three series simultaneously, Hergé was working every day of the year, and felt stressed.
thumb|left|upright|Jo, Zette and Jocko in Cœurs Vaillants Hergé's next Tintin story, The Broken Ear (1935–1937), was the first for which the plot synopsis had been outlined from the start, being a detective story that took Tintin to South America. It introduced the character of General Alcazar, and also saw Hergé introduce the first fictional countries into the series, San Theodoros and Nuevo Rico, two republics based largely on Bolivia and Paraguay. The violent elements within The Broken Ear upset the publishers of Cœurs Vaillants, who asked Hergé to create a more child-appropriate story for them. The result was The Adventures of Jo, Zette, and Jocko, a series about a young brother and sister, plus their pet monkey and the parents. The series began with The Secret Ray, which was serialised in Cœurs Vaillants and then Le Petit Vingtième, and continued with The Stratoship H-22 and finally The Valley of the Cobras. Hergé nevertheless disliked the series, commenting that the characters "bored me terribly." Now writing three series simultaneously, Hergé was working every day of the year, and felt stressed.