Ragasiya Sinegithi is about two close friends, Isha Koppikar and Amrita Arora, who met in college and are now living with each other. Isha Koppikar has a sad past hidden inside her which she hides from everyone, even Amrita Arora.
One day while Isha Koppikar is away, Amrita Arora meets Aashish Chaudhary, whom she starts a relationship with. When Isha Koppikar arrives back from her trip, Amrita Arora has already fallen in love with Aashish Chaudhary.
Isha Koppikar, who wants Amrita Arora for herself, becomes jealous of their relationship. She makes several attempts to break Amrita Arora's relationship with Aashish Chaudhary, but fails constantly. The sad past hidden inside her is reveal at the end of the film.