Tigrotto is a baby tiger who dashes away from a traveling circus near Mimiko's home. Mimiko's household discovers him after two circus representatives, a ringmaster and his assistant, search the property at night.

Exhibiting playful and curious behaviors, Tigrotto consumes Panny's food and naps in Panny's small bed, echoing a Goldilocks-like scenario. Though he initially startles Panny, Tigrotto quickly bonds with the panda cub and joins the makeshift family.

His escape prompts Mimiko and the pandas to seek his origins at the circus. During their visit, Tigrotto demonstrates his ability to balance on a ball, inspiring Panny to attempt the trick. This leads to Panny accidentally entering the cage of Tigrotto's mother, causing momentary panic before Mimiko intervenes, facilitating a peaceful reunion.

When a severe storm floods the region, Tigrotto sends a distress signal via message in a bottle, revealing the circus train carrying the animals is stranded and endangered by rising waters. Tigrotto participates in the rescue alongside Mimiko and the pandas. During this operation, his playful interactions with Panny inside a train carriage inadvertently set it rolling. The uncontrolled train derails and threatens a building, but the crisis is averted.

Following the rescue, Tigrotto remains with the circus but maintains a friendly connection to Mimiko's family. His background is confined to his circus origins, and his development centers on his brief integration into the household and his safe return to his mother.