SATELLITE SHANKAR is about the extraordinary journey of a soldier that brings a nation together. Shankar (Sooraj Pancholi) is a rifleman posted near the LOC in Jammu and Kashmir. He is very popular in his regiment because of his jovial nature. He carries with him an idol of Lord Shankar. He pretends that it's a satellite that can help him connect to anyone in the world. With this little trick, he keeps the officers motivated, despite them not getting leaves. In a firing by the Pakistani forces, Shankar gets hurt. He's admitted in the hospital and though the injury is not serious, he is asked to rest for eight days. Shankar requests his commanding officer, Cheema (Sanjay Gurbaxani) that he'll like to go to his hometown, Pollachi, in Tamil Nadu to meet his mother and get her cataract treated. Cheema agrees on the condition that Shankar reaches the base 8 days later at 8 am. Shankar promises to be back on the stipulated day and time by giving a 'Sainik shapath'. Shankar's colleagues request him to hand over gifts and other items to his family members while he's on his way to his hometown. Shankar then begins his three-day-long journey on the train from Jammu.
As soon as he commences the trip, an old couple in his bogie are asked to leave as they have boarded the wrong station. While helping them find the right train at the next station, Kathua, Shankar ends up missing his own train. He along with Meera Bakshi (Palomi Ghosh), a vlogger, then take a taxi to Pathankot, where their respective trains was to halt. Again, Shankar is not able to make it on time in his train while helping Meera. However, the family member of an army colleague Subedar Jeetu Singh (Pradeep Singh) picks up Shankar's luggage from his train when it halts at a station in Punjab. Shankar reaches Jeetu Singh's residence in Bagha and uses his 'satellite' to spread happiness and solve their problem. Shankar then heads to Agra to finally catch his train to Pollachi.
Yet again, Shankar gives it a miss as he gets busy in saving people who were in a bus that had met with an accident. Interestingly, even Meera is there in the bus and Shankar gets captured in her video. He overnight becomes a hero of the nation. Meera takes it upon herself to find Shankar and she sets off to find him. Her followers cross the million mark and they too get involved in this journey to ensure that Shankar not only reaches his hometown soon but also that he's able to adhere to his 'Sainik Shapath' and report back to base 8 days later at 8 am. What happens next forms the rest of the film.