Ek Phool Char Kante portrays an innocent love sequence between the two super-hit actors Sunil Dutt and Waheeda Rehman. The "Phool" of the title refers naturally to Waheeda Rahman while the four "Kante" are not the expected four eligible bachelors vying for the sole "Phool" but Waheeda i.e. Sushma's four uncles.
Sushma who has become an orphan at a very tender age comes under the custodianship of her four uncles who sacrifice their lives to give her the best possible upbringing. The four uncles excel in four different arts - yoga, theatre, rock music and religion. They also train Sushma in these four skills and she lives up to all of their expectations. Sushma grows up as a confident young woman who enjoys life with friends and their several activities. Sunil Dutt, Sanjeev is the son of a lawyer and is a student of law himself. He encounters Sushma in different situations and he is quite baffled to see her several selves - as a devotee in a temple, as a yogic practitioner, as an actress and as a rock dancer in a bar. Once the confusion gets mitigated, he is cross with her because he sees her with "four" different men little knowing that they are her uncles. Sushma helps to allay his suspicions and confesses love to him. Thus starts their tender love story full of mellifluous songs in the voices of Lata Mangeshkar, Mukesh and Md. Rafi.
The love affair is fraught with impediments - they are the four "kante" in the shape of the uncles who do not approve of Sushma's taste and each one sets out to look for a specialist in his area of interest. Perceiving the difficult situation Sanjeev hits upon a plan - he learns the rules of the four different arts and then presents himself as an aficionado individually before the four uncles. He succeeds in impressing all four of them and each of them feel that he is the best groom for Sushma little knowing that the other three brothers have made the same selection albeit for different reasons.
The climax arrives when Sanjeev is invited by all the four uncles as a part of the pre-marriage rituals. Sanjeev and Sushma then hit upon a plan - Sanjeev refuses marriage to all the four uncles' choices and then the final onus falls on Sushma to choose her life partner. When Sanjeev appears on the scene all the uncles are left open-mouthed till the revelation of the plan. So the "Kante" are got rid of and the duo are left wistfully lilting away the romantic numbers.