कब? क्यों? और कहाँ?

Dharmendra plays a suave CID Officer who romances Babita on board a ship and slowly we get to the plot which involves Babita's dad who dies under mysterious circumstances leaving behind a huge " property" and an evil looking uncle Pran who is after it and her.. Nothing is as it seems as the sinister plot unfolds and our innocent heroine is under threat of losing her sanity and perhaps her life.. Unless of course the hero manages to unravel the plot and save them all..It involves the mystery of dead body in a coffin and things that go bump in the night.