The setting is in India during the war with India and England. The character that was introduced was Teddy and the Mongoose.
The conflict is that the snakes (Nag & Nagina) keep eating or attempt to eat the baby chicks in the garden.
Nag and Nagina had a plan to harm the family. Nag went threw the drains in the bathroom because he was trying to kill the father but Rikki Tikki killed him.
Nagina was mad that Rikki Tikki killed Nag. So now Rikki had to kill Nagina because he knew Nagina wanted revenge, but first he had to kill her babys eggs that hadn´t hatched yet, because there would have been more snakes to help Nagina if her babys hatched.
Rikki Tikki Tavi chases Nagina down her hole and doesn´t come back up for a while so eveyone gets worried, that she killed him.
In the end Rikki Tikki saves everyone by killing Nagina in the hole.