In 2065, a scientist invents a time machine. To prove its capability, he sends it back in time to 2015, programming it to return within forty seconds. However, the machine does not return.

The time machine is seen by three people in 2015 — Elango, a budding entrepreneur whose ideas are rejected by all and is struggling to maintain his relationship with his rich girlfriend Anu, who is embarrassed at the fact that Elango is unemployed; Elango's best friend Pulivetti Arumugam, a fake astrologer; and an inventor Giridhara Parthasarathy, who makes a living by repairing home appliances. The three of them are involved in an accident and witness the time machine while recovering from the shock. While Parthasarathy decides to keep the time machine for himself, he suffers an electric shock and ends up in a coma, prompting Elango and Arumugam to steal the time machine from Parthasarathy's shop. The duo use the time machine to make Arumugam's astrology practice extremely successful by going back in time and finding things lost by people under the guise of astrology. Elango further uses the machine to impress Anu's industrialist father Rajarathinam by going to the future, obtaining the stock market results and successfully "predicting" them in front of Rajarathinam and his company's board of directors. Rajarathinam soon approves the marriage of Anu with Elango.

Things go smoothly until Elango and Arumugam inadvertently thwart an encounter to kill Kuzhandaivelu, a dreaded gangster and extortionist who is targeting Rajarathinam, during one of their trips to the past to find yet another item of Arumugam's client. In the present day, Kuzhandaivelu is plotting to kill Rajarathinam for his role in planning the encounter and also Elango and Arumugam for (unknowingly) attacking him in a parking lot. Elango and Anu's marriage is postponed indefinitely as a result.

Elango and Arumugam go back to the past to fix their mistake, but Kuzhandaivelu accidentally shoots the time machine while fighting a police officer during the encounter, damaging it. The duo find Parthasarathy, who has woken up from his coma but does not remember them, and ask him to fix the time machine. While Parthasarathy manages to fix the time machine, due to a lack of specific parts which have not yet been developed, it can only take the user to a specific time in the past (when Kuzhandaivelu damaged the time machine) and also as the date cannot be changed, the user cannot return to the future. Therefore, the duo decide not to use it. Later, Kuzhandaivelu spots Elango, Arumugam and Anu at a mall and pursues them. He opens fire during the chase, killing Anu. To ensure that Anu remains alive, Elango decides to use the time machine to return to the past and kill Kuzhandaivelu, even though he cannot return. But Kuzhandaivelu spots the duo and while fighting them, all three of them fall into the time machine and go to the past. Kuzhandaivelu destroys the time machine, but Elango manages to trick Kuzhandaivelu into shooting his past self, causing both versions to die. Elango and Arumugam stop themselves from finding the time machine by thwarting the accident involving them and Parthasarathy.

The next morning, Elango wakes up in a bed, remembering only the events of the previous night. He soon finds out, to his surprise, that he is in a marriage hall and that he will marry Anu on that day. He does not remember, to Anu's bewilderment, any of the events which had occurred in the past two months as a result of his usage of the time machine during that period. He finds out that, without finding the time machine, he got a job and managed to impress Rajarathinam with one of his business ideas, leading to his marriage with Anu. Arumugam, who also does not remember anything over the past two months, is happily married. Elango and Arumugam soon find out that Kuzhandaivelu had died two months ago, having been killed in the encounter. They also run into Parthasarathy, who does not recognise them as they had never met.

Since the time machine was never seen, it returned to 2065, making it a success.

Indru Netru Naalai is the directorial debut feature of R. Ravikumar, previously a short film director.^[3] After making the short Zero Kilometer, based on the wormhole concept, he wanted to make a feature film on the same subject, but later found it unsuitable. Nalan Kumarasamy then suggested he make a film based on time travel, and Ravikumar conceived the story of Indru Netru Naalai.^[4] Vishnu Vishal announced he was part of the project in October 2014.^[5] Miya signed on as the lead actress, and to honour her commitments to this film, opted out of My God.^[6] Principal photography began in late October 2014.^[7] In early November, Vishal took a brief hiatus from filming due to developing conjunctivitis.^[8] Filming wrapped in January 2015.^[9] The visual effects and CGI were handled by Phantom Effects.^[4]

The film's soundtrack album and background score were composed by Hiphop Tamizha. The audio launch was held on 12 June 2015.^[10]

Indru Netru Naalai was released on 26 June 2015,^[11] and received positive reviews from critics.^[12] Baradwaj Rangan, writing for The Hindu, called it "A fun ride with a time machine".^[13] S. Saraswathi of Rediff.com gave the film 3.5/5 stars, praising the direction, screenplay, and performances of the cast members. She concluded by saying that Indru Netru Naalai is "worth watching".^[14] Behindwoods stated in its review that Indru Netru Naalai was "A well executed sci-fi film".^[15] M. Suganth of The Times of India gave it 3.5/5 and appreciated the director's way of handling the film's theme.^[16]

On 18 January 2021, a sequel was announced with a puja ceremony. The filmmakers revealed that Vishal and Karunakaran were retained for the sequel. It was be directed by debutant Karthik Ponraj SP with music composed by Ghibran.^[17] However, the film ended up in development hell. In February 2024, Vishal stated that he was unsure whether development was still continuing.^[18]

• Indru Netru Naalai at IMDb