Tera Mera Saath Rahen' depicts the changes in relationship through time. Raj lives in Mumbai with 14-year old brother Rahul who suffers from Cerebral Palsy. Raj spends most of his time taking care of Rahul due to which, his own life takes a backseat. Rahul is totally dependent on Raj. The two are loved by all and neighboring Guptas, their daughter Suman and their son treat them as their extended family. Suman loves Raj but Raj always shrugs her off, as for him his life is dedicated to Rahul. Life takes a turn for Raj when his ex-boss Mr. Khanna asks Raj to meet his niece Madhuri who has come from Delhi after a broken engagement. With time both Raj and Madhuri take a liking for each other. Rahul also accepts Madhuri. Suman however, is not happy. Madhuri makes Raj aware that Rahul needs to be educated and made self-dependent and there are institutions for 'special' children. Raj initially disapproves of the idea but finally accepts that admitting Rahul to such institution will help. But Rahul refuses to be admitted. Despite his refusal, Raj takes Rahul to the institute. Once separated, a sea of turmoil engulfs Raj. Which way the tide turns in the lives of Raj, Rahul, Madhuri and Suman forms the crux of this sentimental drama.