Diyar-e-Dil depicts the story of Bakhtiyar Khan / Agha Jan (Abid Ali) family, who fall apart long ago due to the rebelliousness of Agha Jaan's son Behroze Khan (Meekal Zulfiqar) when he refuse to marry his father's choice and his cousin Arjumand Bedar Khan (Hareem Farooq) to marry Ruhina Arsalan (Sanam Saeed). Behorze left the house to marry Ruhina without the consent of Agha Jaan while Arjumand was forced to marry Behorze's younger brother Suhaib Khan (Ali Rehman Khan). After twenty-years Behorze reunites with family when Suhaib's dies. Their children Faarah Behroze Khan (Maya Ali) and Wali Suhaib Khan (Osman Khalid Butt), marries fulfilling Suhaib last wish to reunite the family. However, Ruhina oppose this decision and leaves Behroze, as a result he dies of her umbrage and his weak health which he had hidden from Ruhina.

With her fathers death Faraah also refuse to accept her relation with Wali and demands divorce, which further increase tension in the family and became the cause of Agha Jaan illness. Wali and Faraah makes an agreement which favors Faraah only if she agree to live with Agha Jaan for three months. Series then shows the affection of Faraah towards Agha Jaan specially Wali and clears her misunderstanding. Other recurring roles include Behroze Sabzwari as Tajamul Arsalan, Tara Mahmood as Zuhra Tajamul, Ruhina's brother and sister in law and their son Ahmad Zeb as Moeez Arsalan who manipulates Farah and Ruhina against Agha Jaan for Faraah's inheritance