Vazhthugal is a story about love, not just love between a man and woman, but the love and affection within an entire family.

Kathiravan (Madhavan) is a successful entrepreneur, socially responsible and an affectionate and dutiful son. He runs Amma, a software company. Kathiravan decides to celebrate his parents' wedding anniversary in an orphanage. He is shocked to find that his friend's parents are residing there. Deeply affected by what he sees, Kathiravan arrives at the conclusion that marriage is an arrangement to separate the loving son from his affectionate parents and that old age homes are filling up with a steady stream of abandoned parents because modern married girls are brainwashing their husbands to banish their parents to old age homes. He begins to view wives as dangerous creatures who mercilessly cut off family relationships. Careful not to involve himself in such a mess, Kathiravan avoids arranged marriage. He also confesses to his friend (Venkat Prabhu) that he would settle down only for a love marriage where he can be sure of his bride's nature before tying the knot.

Kayalvizhi (Bhavana), student of an agricultural college, is the winner in the young achievers' slot. She appears on TV and declares she owes her success and achievement to the support of her large joint family. She remarks that she has scaled great heights in life only because of her happy childhood. Kayalvizhi also mentions her long-term plan to serve society. Identifying similar interests and impressed by her attitude, Kathiravan sets out to Coimbatore to meet her and woo her. He goes to her college along with his friend (Venkat Prabhu). After failing in all his efforts to ignite her interest, Maddy finds an appropriate opportunity when he learns that her family is searching a good interior designer to renovate their traditional family home.

Though not familiar with interior design, Kathiravan bids for the tender and gets it. He then meets a skilled designer (Vijayalakshmi) and explains his mission. With her help, he undertakes the job himself. After a string of meetings, Kayalvizhi finds him good and suitable groom material. Both of them sneak out to Kerala on a jolly trip. A compelling situation lands them in the local police station. When Kayalvizhi's family comes to know about the whole affair, problems crop up. The whole family opposes the affair and tries to force Kathiravan to leave her. Soon, Kayalvizhi's grandfather (Muthusamy), seniormost member of the family, finalizes an urgent wedding, almost a shotgun wedding, between Kayalvizhi and her cousin. That is when shocking truths surface. What follows? A gripping family drama!

Maddy, as usual, is lively, natural, and effortlessly carries out his role with elan. Bubbly charming Bhavana shares great onscreen chemistry with Madhavan. Vijayalakshmi, one of the most-liked characters, the charming interior designer, has given a natural and striking performance.

Avoiding English words in dialogues and character names, offering elaborate introductions to the characters during the first part of the movie, and conceiving idealistic characters who are principled and flawless, are Seeman's signature marks in this movie.

Music by Yuvanshankar Raja has produced some hummable tunes. 'Endan Vaanamum' and 'Unmela Aasapattu' are soft numbers that establish the mood perfectly.

With strong characterizations and realistic convincing situations with a natural feel, Vazhthugal has evolved as a poignant family tale!