盛氏企業發跡自麻將名門，《大三元》的故事也因麻將而起。

原本名不見經傳的盛家，因為一場麻將賽而意外成了代代富貴的大型企業，而他們之所以能致富的關鍵，就是麻將。時光荏苒，來到二十一世紀，盛家企業的長孫曉白（張軒睿飾演）原本要在爺爺過世周年這天繼承家業，但卻因自己的貪玩和不長進而缺席，被二伯父南風（黃仲崑飾演）在典禮上趕出家門，讓他一夕之間從富貴公子哥變成貧窮落水狗。

正當曉白走投無路之時，他被房仲沈無缺（陳嘉樺飾演）收留而來到無連莊，在無連莊房客的幫助之下，曉白決心用麻將奪回屬於自己的一切，但他又要怎麼做才能順利拿回無連莊呢？

Sheng Enterprise has originated from a famous Mahjong family, and the story of Big Three Dragons begins with the game of Mahjong.

The Sheng’s has been unknown to the public, and after a match of Mahjong, it has grown into a huge enterprise for generations unexpectedly. The reason for its success and fortune is Mahjong. Time flies by, entering the 21^st century, the first grandson of Sheng Enterprise, Xiao-Bai (played by Derek Chang) is being designated to inherit the family business on the day of his grandfather’s death anniversary. Yet, due to his pleasure-seeking lifestyle and lacking a sense of responsibility, he is absent from the ceremony, and his uncle Nan-Feng (played by Michael Huang) has banished him from the family. Xiao-Bai turns from a rich young elite to a poor loser overnight.

Just when Xiao-Bai is getting desperate, he has been welcomed by a real estate agent Wu-Que Shen (played by Ella Chen) to a place called Wu-Lan Palace. Receiving the help from the residents of Wu-Lan Palace, Xiao-Bai is determined to win back what belongs to him with Mahjong. But what does he have to do to help getting back Wu-Lan Palace?