Tiger by the Tail (Coelho novel)

The novel tells the story of Rana, an eleven-and-a-half-year-old boy, who is on a mission to save the tigers from disappearing from various Indian forests.

But one day, he discovers a tiger on their doorstep, who demands breakfast and turns out to be Bagha, a friend of Rana's grandfather.

From there, they learn they have to go to Kathmandu, where they meet a holy bull called Kaloji (Agent Number 27), who tells them that the Tigers are going to Tibet.

The missing tigers are all part of an operation to overthrow the governors of China and install the descendant of the last Emperor, 'the General', on the throne.

Rana manages to save the tigers, and by mistake, receives a shot of the elixir, which makes him immortal.