The story of Chaahateknasha revolves around MallikaArora (ManishaKoirala) who is a pop star. She is madly in love with Rahul Kapoor (Aryan vaid), the owner ofR.K. Music world. He also loves her from the core of his heart. However, when he propose to her she politely turns down the marriage proposal and says that she doesn't believe in wedlock. She ardently follows the western lifestyle and is strongly of the view that the instant a couple gets married the love-n-affection glides away from their lives. Though she is physically attached with him she doesn't want to tie the knot.
Story takes a new turn with the downfall of Mallika. Rahul launches a new comer RashmiJaitly (PreetiJhangyani) and aspirant singer and dancer, in his new Music video. Rashmi's debut Music Video is a big hit and she overnight becomes a star. Rahul gets attracted to her and she too looses her heart to him. Rahul decides to marry her.
When this reality of Rahul's falling in love with Rashmi is dawned upon Mallika she is shattered. It's a big emotional shock to her. It's at this juncture that she orders her personal bodyguard Jaidev (Sharad Kapoor) to knock off Rahul. However, the next morning when the alcoholic intoxication vanishes she realises her mistake and calls up Jaidev in order to stop him from killing Rahul. But Jaideve is determined to murder Rahul. The dangerous game begins... Jaidev who is a one-sided lover of Mallika, is all set to eliminate Rahul... and Mallka wants to save her love at any cost...
[from the official press booklet]