Grandpa Hong was discovered by Roger Murtaugh in a boat hiding under a sheet with his family. They had managed to escape undetected after the bigger boat was set on fire. Seeing this, Murtaugh had decided to give Grandpa Hong and the family asylum in his home without the LAPD knowing of it to provide them with shelter until they are granted asylum.
After Grandpa Hong contacts his uncle, it enables Wah Sing Ku to know where the Hongs are at. He and the family are kidnapped by some of Ku's Triad gang members. When Murtaugh and Riggs come home, a fight ensues between them and Ku, who overpower them, and tie them, Trish, Rianne, and Lorna up with ductape and set the house on fire with them in it. However, one of the Hong children, Ping, who hid the whole time, comes out from hiding and cuts Riggs and the rest of them loose. From there, Riggs and Murtaugh go to find the Hongs, without success in finding them.
Grandpa Hong and the rest of the family are brought to the Triads hideout, where it is revealed that the Triads plan to give counterfeit money to a corrupt Chinese General for the release of the Four Fathers. There, Hong meets his elderly uncle, who is an artist and was working on the printing plates and agreed to do the job in exchange for his safe passage in the United States. Ku kills Hong as an example to get the uncle to cooperate. With the printing plates completed, Hong's uncle and Benny are killed to protect the forgery (Hong's uncle) and for exposing the operation (Uncle Benny) and because both had outlived their usefulness.
Riggs, Murtaugh, Lee Butters, Lorna, Detective Ng, Ng's partner, and some other officers locate the hideout, but find only the dead and some of the counterfeit Chinese money are inside. Ng helps them piece the entire operation together.
Roger, who was saddened of Grandpa Hong and his uncle's death, made a solemn promise to Hong that he would find his family and bring them to safety, and bring his murderers to justice.