The story follows the experiences of a young mongoose named Rikki-Tikki-Tavi (for his chattering vocalizations) after he is adopted into a British family residing in India, as a pet and as protection against venomous cobra snakes.
After becoming friendly with some of the other creatures inhabiting the garden, Rikki is warned of two cobras Nag and Nagaina, who are angered by the family's presence on their territory. Accordingly, Nag enters the house's bathroom before dawn but is attacked by Rikki. The struggle that ensues awakens the human family and the father kills Nag with a shotgun.
The grieving Nagaina attempts revenge