Members of Five-O are seen arresting people for prostitution and gambling. Kumu boss Cappy Pahoa (Manu Tupou), talking to Jimmy Rego (Reni Santoni), boyfriend of his daughter Kini (Elissa Dulce Hoopai), wonders why they are hitting such little operations.
Steve McGarrett meets with members of HPD and says that if they don't clean up local mob activities, the Feds are going to step in. He wants HPD's co-operation in busting small time crooks to divert attention from a larger-scale crackdown on the kumu (Hawaiian mafia).
In the low-rent district, Chin Ho is posing as the San-Francisco-based nephew of an old man who runs a pool hall. When two punks, Kimo Napali (Rod Aiu) and Brian Liu (Peter Kalua), visit the pool hall asking for protection money, Chin tells them he wants to meet with their boss that evening. One of them watches Chin making a phone call. When Chin is finished, the two tell him they want him to come and meet their boss right now. They take him to see Rego, who throws questions about San Francisco at Chin which he can't answer properly. Rego tells Chin that they know he works for Five-O. Chin fights with them. Rego pulls a gun.
While McGarrett meets with HPD members in his office, Napali and Liu drive by the Iolani Palace and dump Chin's dead body in front of it as a horrified tourist screams. Later, McGarrett is beside himself with grief, vowing to get Chin's killers.
Pahoa is upset and talks to Rego, who acts as if he knows nothing of Chin's death, saying "somebody did us a favor." Pahoa says that McGarrett will not easily accept the death of such a high-profile law enforcement officer. He tells Rego to lay low for a while. Rego figures he can take care of the Five-O boss, but Pahoa says "there is no way to reach McGarrett." Pahoa tells his right-hand man Billy Swan (Vic Malo) to keep an eye on Rego.
McGarrett consoles Suzi (Jean Marie Hon), Chin Ho's daughter, who arrives from San Francisco. He says that his men are "the only family" that he knows, and tries to accept responsiblity for Chin's death. Suzy mentions that her mother died some time before.
Lab technician Charlie determines that Chin was killed with a .22 caliber Magnum fired into the base of his brain -- "the work of a pro," according to McGarrett.
McGarrett visits Pahoa. He says, "You killed my friend," to which Pahoa replies that he never killed anyone. McGarrett tells Pahoa to "cut the bull" and find out who did it to prove that he is a good citizen. As McGarrett is about to leave, Pahoa says that he has friends in high places, to which McGarrett counters, "And so have I."
McGarrett has dinner with Suzi. He says that Pahoa became leader of the syndicate 10 years ago. Suzi brings up the fact that she knows Kini, Pahoa's daughter. Suzi wonders if she can help the investigation, but McGarrett cautions her not to get involved. She suggests talking to Kini, who came to the funeral with Rego. Rego was born on the Big Island, but grew up in San Francisco and returned home recently.
Napali and Liu visit restaurant owner Yung Sen (Gary Kau), demanding to know who tipped off Chin Ho about the protection racket. Billy Swan watches outside.
Meanwhile, the Five-O team finds a list of contacts in Chin Ho's undercover hotel room. McGarrett tells Danno to check out Rego via the Justice Department in San Francisco.
Danno and Duke visit Yung Sen, who tells them he will identify the men who were threatening him when they return on Saturday. However, Napali and Lui deliver a bucket of fortune cookies rigged with dynamite to the restaurant, and when Yung opens it, it explodes, killing him and two other employees.
McGarrett shows up at Yung Sen's restaurant just as the bodies are being carried out. Back at the office, info from San Francisco reveals that Rego has a record of six arrests and one conviction for running a protection racket in Chinatown there.
McGarrett hauls Rego into his office and grills him about the murder. Rego has a bogus alibi and suggests they settle things between the two of them. McGarrett is hard pressed not to take him up on the offer.
A waitress in the restaurant recalls that just before the explosion a truck from Hawaiian Restaurant Supply, one of Pahoa's companies, showed up. McGarrett arranges for Pahoa to be arrested at a cockfight and thrown into jail -- his first such offense. McGarrett visits Pahoa in the slammer, saying he suspects Rego is behind Chin's murder. McGarrett says he will impound all of Pahoa's trucks until he finds some clues.
Rego and Kini join Suzi for a swim at her hotel. Pahoa calls Rego away, telling him that Billy Swan saw Rego's punk pals at the restaurant prior to the murders. Rego admits that he "wasted that Chinese cop as an example." Pahoa says "there is no place in kumu for hotheads and fools," suggesting that Rego and Kini take a trip to Europe. When Rego gives him some mouth, Pahoa says he can leave either on a plane or in an oil drum.
In Rego's apartment, Suzi snoops through the closets while Kini takes a shower. Rego almost catches her.
After Five-O finds the truck used by Napali and Liu, the two punks are seen tailing McGarrett. The tables are turned as McGarrett ends up tailing them, finally running them off the road and arresting them.
McGarrett once again cautions Suzi about getting involved trying to find the killer of her father. She says that she's "not doing anything dangerous," and that she only met Rego at the funeral. Danno says both Napali and Liu have records in San Francisco. The lab finds traces of the explosive used in the restaurant in the punks' car.
Rego contacts Kini, saying that everyone is looking for him. They make plans to go away together. Suzi jumps from the hotel roof to Rego's balcony and finds a suitcase of money and a gun in his room. She takes the gun with her. Kini pleads with her father to go away with Rego. Pahoa says he will help if he knows where Rego is. She says "a little house on the North Shore."
At the Five-O office, Suzi gives Rego's gun to McGarrett. Bullets fired from it match the ones which killed Chin Ho.
McGarrett visits Pahoa, who tells him where Rego is hiding, saying "we're doing each other a favor."
Five-O arrives at Rego's hideout. Rego tries to escape but is cornered by McGarrett. Rego begs for his life as McGarrett almost shoots him. McGarrett tells Danno, "I want to book this one. I think Chin would have liked that."