Once upon a time, the forces of good and evil clashed in Lanka. The monkeys built a bridge to Lanka with stones that floated on water. Monkeys fought against demons in this war and Lord Rama had taken the task of slaying Ravana. During one such battle in this war, Indrajit (Ravana’s son) had wounded Lakshmana badly. Sushena (a physician) says that Lakshmana will survive only until daybreak and by then he needs to be treated with the Sanjivini herb. Now, this herb could only be found in the Dronagiri mountain in the Himalayas. So, Hanuman immediately flew to the Himalayas to get the herb.
Somehow, Ravana came to know about this plan and decided to disrupt it. He sends a demon named Kalanemi. Kalanemi disguises himself as a sage and tries to confuse Hanuman. But Hanuman comes to know about the true form of the sage and kills him. When Ravana comes to know about his death, he forces the sun god to rise much earlier so that Lakshmana would die. The sun god rises, but Hanuman does something extraordinary here. He becomes very big in size and encloses the sun in his palm, so that it still remains night. Then, he continues the search for the Dronagiri mountain.
Seeking the help of an old lady, he finds the route to the mountain. But he is unable to find the Sanjivini herb. Instead, he once again grows big in size and uproots the whole mountain. Hanuman carries the entire dronagiri mountain to the battlefield where Lakshmana is on the verge of death. Sushena finds the Sanjivini herb and uses it to treat and save Lakshmana. Lord Rama thanks Hanuman profusely for his help and considers him as his own brother. Hanuman then releases the sun god. The war in Lanka continues with Lakshmana killing Indrajit and the tide turning in favour of Lord Rama.