Aditya 369

The film opens in 1991 with Professor Ramdas pursuing experiments on the time machine Aditya 369. He dreams of revealing the future by proving time travel is possible, even as Raja Varma plots the theft of a priceless 16th-century Vijayanagara diamond from Salar Jung Museum.

During a school trip to the Salar Jung Museum, Kishore witnesses the theft of the Vijayanagara diamond carried out by Raja Varma’s accomplices. The guards are overwhelmed, and the crime reveals Varma's reach behind the scenes. The incident seeds the central mystery of the film.

Krishna Kumar rescues Kishore after the hospital incident and takes him there. He becomes involved with Ramdas’s family and starts to fall in love with Hema, who dismisses her father's experiments as useless. This personal stake strengthens the ties between science and ordinary life.

Krishna Kumar visits Ramdas’s house and discovers the time machine Aditya 369. The device breaks down soon after, dampening their hopes of walking through time. The failure sets the stage for the later realization that they might still travel back to the day of the robbery.

Kishore learns about the time machine from Hema and realizes they could travel back to the day of the robbery. The idea excites everyone but also hints at the dangers of tampering with history. They begin to plan a risky attempt to recover the diamond.

One night, Kishore activates the time machine with the hospital children; Krishna Kumar, Hema, and a police constable chasing a thief are accidentally pulled into the machine. They arrive in 1526 CE during the Vijayanagara Empire under Sri Krishnadevaraya.

Krishna Kumar saves Simhanandini, a royal dancer, from an assault and is invited to the royal court. He impresses the emperor by reciting a poem not yet written by the court poet, Tenali Ramakrishna, earning cautious trust. The court begins to see him as a genuine visitor from the future.

The group learns the diamond has divine power that reflects on the eve of Karthika Pournami and is prophesied to be stolen twice—once in Krishnadevaraya’s time and again after 500 years. They witness the diamond radiating seven colors in the moonlight during a ceremonial moment.

Simhanandini, humiliated by Krishna Kumar, conspires with Senadhipathi to frame him for the diamond’s theft in the emperor’s eyes. Tenali Ramakrishna uncovers the truth and is abducted, but he escapes with the help of Manjari, the constable’s love interest. Krishna Kumar faces a death sentence before the truth comes to light.

Tenali Ramakrishna, aided by Manjari, reveals the truth to the emperor, clearing Krishna Kumar’s name. Krishna Kumar, Hema, and the constable escape again, this time through the time machine as the past collapses around them. They return to the present with a new sense of urgency.

Krishna Kumar, Hema, and the constable attempt to return to 1991 but the machine malfunctions and drops them into 2504 CE. They find a post-apocalyptic Earth where radiation has devastated the surface and people live underground.

In the future, they learn from a past news report that Krishna Kumar died in 1991 while attempting to retrieve the diamond. The revelation forces them to plan a risky return to their own time, aware that not all information from the future is available.

The trio finally manages to return to 1991, only to find Raja Varma has kidnapped Ramdas and Kishore to seize the time machine. Krishna Kumar undertakes a perilous rescue mission to retrieve them.

A climactic fight with Raja Varma ends on a hilltop where the time machine explodes. Krishna Kumar survives by leaping off the cliff before the blast. He realizes the future lacked crucial information about the machine’s consequences.

Back in the present, Ramdas declares the time machine has no practical value for society or the country and focuses on other projects. Kishore vows to become a scientist like Ramdas, inspired by the journey. The story closes on a note of renewed scientific curiosity.