'Mathapoo' is a heartwarming and sweet romance that revolves around Karthik, a young man who moves from Madurai to Chennai and falls in love at first sight with Pooja, a beautiful and sweet young girl who helps him out.
Karthik would dearly love to marry Pooja and begin a lifetime of happiness and companionship with her, but, despite her family's approval, Pooja mysteriously rejects the offer.
The reason behind Pooja refusing to accept Karthik's love is a little insipid and cliched. She was taken to the police station after her male friends tried to date rape her and her mother (Geetha) blamed her for the fiasco. So, she has decided never to marry just to prove to her mother that she was blameless. But bafflingly, she continues to stick to her stand even after her mom has come to realize her virtuousness and wants her to marry Karthik.
Will the magic of love and Karthik's unceasing love and devotion manage to win Pooja's heart and break down the walls she has voluntarily built around her heart?