'Maruthanaatu Ilavarasi' is a well-woven story about a king (Veerappa) with two wives (one played by Saraswathi and the other does not appear in the movie!) and an evil-minded Minister (Chakrapani) whose sister is the younger queen. The two become pregnant and the evil genius persuades the king to believe that the senior queen poisoned the junior queen out of sheer jealousy; the king believes but takes no action. The frustrated Minister tries to eliminate the pregnant queen, but she is saved by a courtier whom the Minister kills. The pregnant queen escapes many trials and gives birth to a son (MGR). He grows up and meets a young woman (Janaki) and her friend (Nagaratnam) and falls in love, unaware that she is a princess. Their love grows, but when he comes to know that she is a princess, he distances himself from her. After many trials, the two come together and live happily.