Based on Agatha Christie's The Mirror Cracked, Shubho Mahurat is a murder mystery set in Calcutta and made in the style of India's new cinema. It is the story of two actresses, Kakoli (Kalyani Mondai) and Padmini Choudhuri (Sharmila Tagore), who have dark and hidden resentments about each other from past years of working together.

Choudhuri has since retired and lives in America but returns to Calcutta to produce a film that her unsuccessful director husband, Sandip Ray, is making in which Kakoli has the lead role. During the mahurat (a traditional party held to celebrate the filming of the first shot of a new production) Kakoli, who is now a drug addict, is given a poisoned drink. She dies at home later that night in the presence of young journalist Mili (Nandita Das) who accompanied Kakoli home.

Suspicion falls on everyone involved with the ill-fated movie and though the police are investigating the case, the culprit is found thanks to the talents of Mili's Aunt (played by Bollywood star Rakhee), who in Miss Marple style figures out who murdered Kakoli and why.