Anokhi Ada (1948)

Prakash and his beautiful sister live an impoverished lifestyle in a rented room in Bombay. They do not even have enough to eat and are three months behind in their rent. The neighborhood has put pressure on their landlord to evict them as they suspect his sister of being overly friendly with a homeless male who calls himself Laatsaheb. Things only get worse after Prakash is killed and his sister decides to re-locate by train. While traveling she finds her co-passenger is none other than Laatsaheb - who confesses that he loves her. Before she could respond, the train meets with an accident, he survives with minor injuries but she loses her memory, is hospitalized and presumed to have lost her mind also. She manages to escape and ends up with Imperial College's Professor Nath - who gets smitten by her beauty, calls her Kamini, assures her that she has always lived with him, and decides not to treat her medically - so that she can be his forever.