Ready starts with ready-witted Prem (Salman Khan) helping his childhood friend Khushi (Zarine Khan) to elope with Raju (Ajay Devgn). Khushi’s intended bridegroom Gaurav (Arbaaz Khan) reveals that he also has a girlfriend, Kiran (Kangana Ranaut), whom he wants to marry. The elopement angers Khushi’s father, Mr. Pathak (Mithilesh Chaturvedi) and Prem’s family, the Kapoors. Prem manages to pacify his family members.
The Kapoors decide to get Prem engaged to Pooja. Prem is sent to receive Pooja at the airport; however, he deliberately goes to the wrong terminal to avoid meeting her. A young woman named Sanjana (Asin), who has just run away from her own wedding, overhears Prem telling his uncle about ditching Pooja. Since nobody from Prem’s family has ever seen Pooja, Sanjana pretends to be Prem’s intended fiancée. Sanjana, posing as Pooja, goes to stay with the Kapoors and wins the hearts of the entire family, except Prem, who gets irritated with her.
Meanwhile, Sanjana’s maternal uncles, Amar Choudhary (Akhilendra Mishra) and Suraj Choudhary (Sharat Saxena), who are rivals, try to search for her. Each uncle wants Sanjana to marry his respective brother-in-law to inherit her wealth. Sanjana and Prem escape from Suraj Chaudhary’s goons by taking a lift in the car of Mr. Lehri (Sudesh Lehri). Prem outwits the goons and sends Suraj’s son Aryan into a coma while escaping. Suraj Choudhary takes the help of Mr. Lehri to get to know who ran away with Sanjana.