Ek Din Achanak Hindi , English Suddenly, One Day is a 1989 art film directed by Mrinal Sen, based on a Bengali novel, Beej by Ramapada Chowdhury.
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 Professors 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?
Source: Wikipedia