King of Mahjong centres on the decade-long feud and eventual reunion of Wong Tin Ba and Fatt, two top disciples of the legendary mahjong maestro, Master Ru.
20 years later, Wong Tin Ba, who is now a world-acclaimed mahjong champion and magnate, shows up in Ipoh to challenge Fatt to a final showdown – The World Mahjong Championship. Despite Wong’s insistence, Fatt declines to join the competition as he is determined and contented to lead the life of a commoner.
In a bid to force Fatt into the showdown, Wong abducts Fatt’s wife, Ramona, and threatens her to be on his alliance. Fatt has no choice but to join the championship as Wong holds his wife hostage. On the mahjong table, Fatt and Wong compete as the finalists; Master Ru’s secret legendary mahjong move and the truth comes to light as the winner emerges.
