The story of the film revolves around the lives of two individuals — Satvinder Kaur Bedi, a 68-year-old lady, and Oliver, her 10-year-old young boy neighbor. When they meet, they discover that both of them share some common problems regarding loneliness. Soon, they develop a strange but sensitive relationship which gains momentum over the period of time. The ways in which they overcome several hurdles in the form of age, language and culture, and finally communicate with each other to create an intimate long-lasting companionship forms the climax of the story.

Tashi explores various facets of life, with a focus on the simple story telling about the delicate relationships between parents and their children, between siblings, between spouses as well as between strangers. The name of the film, Tashi, is inspired by the Tibetan word, meaning 'auspiciousness'.