Ashok (Shammi Kapoor) cannot forget that his childhood prank has cost his little sister her eyesight. To atone, he wants to restore her vision but cannot afford the cost of the operation. So he takes up a strange assignment. Sarojini Devi (Lalita Pawar), who hates love marriages, because her twin sister had a disastrous one, hires Ashok to break up the love affairs of her two younger grand-daughters and make her eldest grand-daughter, Asha (Babita), who hates men, amenable to marriage. Ashok carries out his task admirably, but also falls in love with Asha. Furious, Sarojini Devi first exposes him and then sacks him. Ashok goes home to find that his blind sister Roopa (Jayanthi) has been raped and thinks that she has commited suicide. Swearing revenge he sets out in search of the rapist (Pran), who becomes Asha's fiance and abducts her grandmother to replace her with evil twin sister. Will Ashok find his sister? Will Roopa get back her eyesight and her brother's love? Tumse Achha Kaun Hai is memorable for Shammi Kapoor & Lalita Pawar's performances and has some foot-tapping music by Shankar-Jaikishan including the title song, 'Tumse Achha Kaun Hai', counted amongst the many hit numbers that Mohd. Rafi sung for Shammi Kapoor.