Kahiin to Hoga is an Indian soap opera which aired on STAR Plus between September 2003 and February 2007. The show was created by Ekta Kapoor of Balaji Telefilms. The romantic-drama series was show was one of the famous television program during its airing period which helped Star Plus capitalize the television market in the 2004-2006 era. Kahiin to Hoga suffered huge loss when its lead Rajeev Khandelwal left the show in between.
Kashish(Aamna Sharif), Mouli, Mahek, Charu and Kanan are five sisters living in Shimla. Their father, Prof. Sinha, is an idealistic college teacher. One day, Kashish accidentally hits a car belonging to Sujal Garewal, a dynamic young businessman. Later, she goes for a job interview to his office. She assumes that she will not get the job, but Sujal hires her. Sujal(Rajeev Khandelwal) works for a business enterprise started by his father, Chetan Garewal, in partnership with close friend Lalit Raheja. The Raheja and Garewal families live in the same house. Sujal's best friend is Lalit's son Piyush. Sujal has a spoilt and arrogant younger brother Rishi, who flirts with both Mouli and Mahek. Piyush's younger brother, Varun, secretly loves Mahek.
Kashish and Sujal fall in love with each other. She writes a love letter to him and leaves it on his desk. Rishi, who dislikes Kashish, sees the letter. He deliberately puts Piyush's name on the letter. When Piyush sees the letter, he thinks that Kashish likes him and begins to feel the same way for her. Lalit Raheja and Prof. Sinha decide to get Piyush and Kashish married. Meanwhile, Sujal and Kashish verbally declare their love to each other. Kashish assumes she is about to get engaged to Sujal. On the day of the engagement Kashish is shocked to see Piyush as her fiance. But she decides to stay quiet to prevent embarrassment and humiliation for her family. However, Sujal sees the letter with Piyush's name on it and thinks that Kashish is cheating on him. He breaks up with her and goes into depression.