Ek Din Achanak (Hindi: एक दिन अचानक, English: Suddenly, One Day) is a 1989 art film directed by Mrinal Sen, based on a Bengali novel, Beej by Ramapada Chowdhury.
One evening, in the midst of torrential rains, a professor (Shreeram Lagoo) goes out for a walk and fails to return. As the evening stretches into days and the days into weeks with no sign of him, his family struggles to regain their footing and to understand what might have caused him to leave. Slowly they return to their daily activities. The professor’s son Amit (Arjun Chakraborty) establishes his fledgling business; his younger daughter Sima (Roopa Ganguly) resumes her studies at college; and his elder daughter, Neeta (Shabana Azmi), the backbone of the family, returns to her office job.
Behind the facade of normalcy, though, the family is deeply wounded. Amit enjoys success in his business but is bitter and dour. Neeta has a very patient and supportive boyfriend (Anjan Dutt), but the relationship is stuck in a holding pattern. And their mother (Uttara Baokar) suffers debilitating depression. Their hesitant attempts to piece together the professor’s state of mind before his disappearance raise more questions than they answer: Was he having an affair with a former student (Aparna Sen)? Was his academic career crumbling? Was he a plagiarist?