[1] The show was created by Ekta Kapoor of Balaji Telefilms and starred Aamna Sharif, Rajeev Khandelwal and Gurpreet Singh.

One day, Kashish accidentally hits a car belonging to Sujal Garewal, a rich, young businessman.

Sujal works for a business enterprise started by his father, Chetan Garewal, in partnership with close friend/brother-figure Lalit Raheja.

Sujal has a spoilt and arrogant younger brother, Rishi, who flirts with both Mouli and Mahek.

Kashish and Sujal eventually fall in love with each other as they grow even closer since seeing each other daily at work.

Rishi, who dislikes Kashish, sees the letter and deliberately puts Piyush's name on it.

However, Sujal sees the letter with Piyush's name on it and thinks that Kashish is cheating on him.

Varun soon confesses his love for her and proposes but she refuses as she doesn't want to be in a relationship again.

As Mahek begins to live in the Raheja/Garewal household, Rishi flirts with her and grows close to their son.

To punish him, Kashish decides to marry Sujal and live close to him to get access to his home and business and to destroy him.

Sujal is devastated and believes he has lost Kashish, but finds relief after he sees her lying unconscious yet deeply wounded close to the bottom of the cliff.

When Kashish sees Sujal nursing to his deep wounds, she offers to aid him.

While the entire Raheja and Garewal house is shaken by Kashish's betrayal and of her false understanding of Sujal as Piyush's killer, Akshat, Rishi and Kashish's sisters take Sujal's side and are determined to prove him innocent.

Eventually, Kashish begins learning of clues that point towards Sujal's innocence and is startled.

Kashish vows to prove Sujal innocent and to set him free, to live a life with him again.

Archie was jealous of Sujal's love for Kashish and wanted to get rid of her, but Piyush died in the car crash meant for his wife.

Mouli finds out about Rishi's flirtatious behavior behind her back and wants to return home but her father refuses.

On his way to meet Kashish, Sujal has an altercation with some criminals, falls into a river and is presumed dead.

Charu soon grows attracted to Tushar and eventually falls for him after misunderstanding Kashish and Akshat to be getting married.

It is then revealed that Charu was faking her illness in order for Sujal to grow closer to her but the truth comes out and everyone shuns her.

During a party Charu commits suicide leaving Akshat in despair but it is rumored that she was mysteriously killed.

Mouli falls for and marries Siddharth, the brother-in-law of a rich man named Shabbir Ahluwalia.

So, Kashish marries Shabbir Ahluwalia in order to find Charu's killer.

Soon, Rishi turns over a new leaf and begins to care for Mahek and they start to love each other again.

There, they meet Abhishek Chauhan, a navy officer and a look-alike of Piyush (who is later found to be his identical twin).

Kashish, Mahek and Rishi begin living happily until Swayam returns.

[6] Kahiin started with a rating of 5 TVR in the premiere week at number 31 of most watched Hindi television series but gradually increased and entered top 10 programs.

[7] Kahiin to hoga became one of the most popular Indian television programs by achieved the milestone of getting TVR of 10.77 in second week of 2005, despite aired at 11:00 pm (IST) slot.

[11] The show to this date is remembered as a classic during Golden Period of Indian television fiction.

[7][12][13][14] Mid-Day stated that the series was popular mainly because of the lead characters Kashish and Sujal's crackling chemistry.