Baby Do Die Do follows the life of Baby Karmakar (Huma Qureshi), a deaf and mute woman leading a dangerous double life in Mumbai. While her mother (Mangal Kenkare) believes she lives an ordinary life, Baby secretly works as a highly skilled assassin under the guidance of her mentor and handler, P. M. Jain (Chunky Panday). Haunted by the childhood loss of her twin sister and burdened by the emotional cost of her profession, Baby yearns for a life filled with love and normalcy. She finds hope when her neighbour, Amandeep Singh Siddhu (Rachit Singh), an aspiring singer and music teacher, falls in love with her, and she gradually opens her heart to him. Meanwhile, Jain is hired by ruthless builder Zafar Katkar (Sikandar Kher) to eliminate his business rival, Mikky Murjhani (Himanshu Malik). After Jain's trusted associate Manu (Marudhar Shekhawat) fails to complete the mission, Baby steps in and successfully executes the assassination. But the high-profile killing draws the attention of DCP Anjum Khan (Seema Pahwa), setting off a tense game of pursuit that threatens to expose Baby's secret life. What unfolds next forms the rest of the story.