Set in the cable internet turf war of Mumbai, Sonali Cable is the story of a girl Sonali (Rhea Chakraborty) and her ‘internet boys’, including her brother Sadda who are working in their own internet cable wire shop. One day when a new police station starts in their region Sonali reaches there for giving connection. There she meets her old school friend, now graduated from a university in the U.S., Raghu (Ali Fazal) who remembers her name, and even her roll number 43 while they were studying in school. They fall in love.

During that time Sonali faces a problem because of a big industrial company "Shining" starts providing broadband services. During Ganapati festival Sonali and Raghu consummate their love. On the same night Sadda, Sonali's brother gets hit by some local goons trying to vandalize their shop. Sadda succumbs to his injuries. Sonali gets determined to take revenge on the company.

Sonali Cable is like a 'David versus Goliath' story, in the thick of the cable internet turf war in Mumbai. At last Sonali wins the war by spying on the corruptions of the people who worked against her. Later Sonali starts an internet cable shop in the name of her brother Sadda. Raghu joins her in the shop and in her life.