Plot

After mobiles start mysteriously flying out of the hands of people in Chennai, Dr Vaseegaran summons his trusted robot Chitti to ward off the bird-shaped supernatural powers of Pakshirajan.

8 years after Chitti was dismantled due to destruction he caused. Vaseegaran has created new human robot Nila which can understand human feelings better. The cell phones in the city start to disappear from everywhere. A creature in the form of bird creates havoc in the city causing destruction. Vaseegaran believes it to be the fifth element force and decides to get Chitti back in action. When Vaseegaran traces the location of missing cellphones with help of Chitti and Nila he finds that its not the fifth force but a human force done by late professor Pakshi Rajan.—alex.mjacko@gmail.com

When mobile phones start mysteriously flying out of the hands of people in Chennai, Dr Vaseegaran and his android assistant Nila are called in for help. The city is under a threat from the supernatural powers of Pakshirajan, a deadly winged monster seeking revenge on mankind for harming birds with mobile radiation. Dr. Vaseegaran is forced to reassemble his robot 2.0, the upgraded version of Chitti to fight against Pakshirajan and save the world.—Santhosh

Eight years since Chitti's disassemble, a distraught man commits suicide at a cell tower surrounded by gray skies and dying birds. The next day, several possessed cellular devices take to the skies with a hive like behavior, controlled by an entity not seen before. Dr. Vaseegaran, a reactivated Chitti, and robotic assistant Nila take it upon themselves to find out what the hostile spirit wants and how to put a stop to him.—Almultimavenger

Dr Vaseegaran has to fight an unknown natural force targeting cell phones and their companies.When things go beyond control he decides to reboot his dismantled Robot Chitti.After Chitti tackles the force on his own Vaseegaran is surprised to know that the unknown force is Pakshi Raja who protested against cell phone towers to save the birds.—alex.mjacko@gmail.com

Vaseegaran (Rajinikanth) (a scientist who created a sophisticated robot in his likeness with a desire to commission it into the Indian Army. He introduced the robot as Chitti) introduces Nila (Amy Jackson), a domestic and feminine humanoid robot created by Vaseegaran, whose name is a contraction of "Nice, Intelligent, Lovely Assistant".

This robot is meant to be a friend, helper, and caretaker. It can drive, perform forensic analysis, jump walls and disable electronic alarms. Vaseegaran introduces new humanoid robot who is his personal assistant, to a group of students. Shortly thereafter, a student's smartphone suddenly starts flying, exhibiting avian characteristics.

Before long, cell phones all over Chennai begin to fly away, leaving the city in chaos. At an emergency council meeting initiated by the government, Vaseegaran enunciates that it is beyond conventional science to fight what he considers a fifth force and proposes reinstating Chitti (an advanced "andro-humanoid" robot. It was designed with a speed capacity of 1 Terahertz (Hz) and a memory capacity of 1 Zettabyte.), which was dismantled in 2010.

But Dhinendra Bohra (Sudhanshu Pandey) (A scientist and the son of Dr. Bohra, who was once killed by Chitti. After his father's death, Dhina assumes the robot to be Vaseegaran's alter-ego and wishes to take revenge on him. He happens to be the first person to voice against the reinstatement of Chitti in the government meeting. Later, he also becomes jealous of Chitti's resurgence and, sneaking into the AIRD Institute, he frees Pakshi's aura from the containment circuit.), who lost his father to Chitti's anger, opposes, and the council decides to seek help from the military, thereby vetoing Vaseegaran's proposal.

The growing stream of cell phones leaves havoc in its path, killing a mobile phone wholesaler Jayanth Kumar (Ishari K. Ganesh), a transmission tower owner Manoj Lulla (Kaizaad Kotwal), and the state's telecommunications minister Vaira Moorthy (Kalabhavan Shajohn). In addition, the swarm of cell phones takes the shape of a giant eagle claw to uproot all cell phone towers in a 200 Kms radius around Chennai. To prevent further damage, S. Vijay Kumar (Adil Hussain), the Home Minister, unofficially gives Vaseegaran permission to rebuild Chitti. Chitti traces the mobile phones. Vaseegaran then learns from Chitti that the eagle bird (made by the cell phones) is powered by the aura of a human being, which exudes negative energy. The radiation from the antennae of such signal transmitters and auras of other living organisms are positively charged while those of the dead are negatively charged, allowing the parabolic transmitters to repel the bird. Had it entered the electromagnetic field produced by the transmitters, the radiation from the antennae would neutralize the bird, preventing it from reassembling. Vaseegaran replicates a smaller version of those transmitters to destroy the bird. During neutralization, Vaseegaran learns that the negative aura is from Pakshi Rajan (Akshay Kumar).

Pakshi Rajan used to be an ornithologist who owned the now abandoned house where birds would come and live with him. Gradually, high-frequency radiation from the newly set up cell towers starts killing the birds due to the rapid growth of mobile phone industries. Pakshi then visits Jayanth Kumar, Manoj Lulla, and the telecommunications minister in order to request them to stop their unjust and unlawful activities but it is in vain. He also organizes conferences and protests against the exorbitant use of cell phones but receives no support. Ultimately, all his birds die, and a distraught Pakshi Rajan hangs himself to death from a cell tower. His life energy, along with that of numerous dead birds, combine together to form an aura that manipulates mobile phones into any form through electromagnetic radiation.

Chitti reactivates the transmitters and neutralizes Pakshi, storing his energy in a containment circuit. Chitti is hailed as a hero and Vaseegaran receives an order for 500 units of Chitti from the Indian army. But jealous of Chitti's resurgence, Dhinendra sneaks into the AIRD Institute and frees Pakshi's aura from the containment circuit. The aura enters Vaseegaran, enabling Pakshi Rajan to possess his body and attack humans who still possess cell phones. Chitti hesitates to kill him, as it would mean killing Vaseegaran too. Taking advantage of this, Pakshi disassembles Chitti. Vaseegaran takes control of his body long enough to instruct Nila to activate protocol 2.0 for Chitti.

Nila takes Chitti back to the lab and rebuilds its body, replacing its microchip with the red chip created by Bohra, which results in Chitti's violent configuration, version 2.0, being in control. Nila constrains it from harming anyone but Pakshi Rajan. Chitti then creates more versions of its likeness. Meanwhile, Pakshi takes over a crowded football stadium and exposes Dhinendra to radiation from the nearby cell towers, incinerating and killing him. Chitti, along with its army of robots, arrives and confronts him, resulting in a battle between the two. However, Chitti battery drains, and it rushes to the nearest power station.

During this time, micro-bots resembling Chitti, called Kutti version 3.0, arrive mounted on white pigeons and confront Pakshi Rajan, who cannot kill the spectators now as it would mean that the pigeons would also get killed. At one point Pakshi's aura leaves Vaseegaran's body. The micro-bots then lead his aura to the signal transmission site, where Pakshi Rajan is eliminated. Vaseegaran recovers in the hospital and tells Vijay Kumar, who comes to see him, that he feels Pakshi Rajan was a virtuous person who became a victim of the corrupt society. He also suggests that everyone should limit the use of phones and conserve the lives of birds as much as possible. Chitti, now restored to its original version, begins a relationship with Nila, to which Vaseegaran gives his consent.

In a post-credits scene, Sana asks Vaseegaran over the phone about the probability of mobile phones flying again. Immediately, Vaseegaran's mobile flies out of his hand and morphs into Kutti 3.0, saying, "I am your grandson".