18 Grams of Love

What happens when two friends suspect their wives of infidelity? To allay their suspicions, Ah Hui and Zihua decide to test their wives by having the other write a love letter to the other's wife, to see if she will respond. As they get caught up in their ploy, they start to ignore their wives. In turn, their lonely wives begin to respond to the letters. One day, Zihua's wife writes back to Ah Hui and proposes a meeting in a love hotel...