Hawaii Five-O” fans had reason to rejoice on April 5, as the elite force of crime-fighters came back to their steadfast slot in the CBS Friday night roster. It may have seemed like eons since “Hawaii Five-O” had its hooks into a perpetrator, but, in actuality, only two weeks of NCAA “March Madness” preempted the police drama. The return this week with Episode 20 of Season 9, “Ke ala o ka pu" (Way of the Gun) was meaningful and satisfying. However briefly, the storyline assembled the full contingent of “Five-O” to work an initial case of good intentions gone wrong, only to discover that a single gun had strands of history running through generations of the force.

A good girl after a gun

Bonnie Pearson (Makenna James) is a teenage daughter stuck between a rock and a hard place, as she sees it. Her parents, Owen (Jason Brooks) and Kiana (Mia Adams) are in the midst of a messy, drawn-out divorce, and mom has a boyfriend, Michael Kerrigan, who has been inflicting worse and worse beatings upon her. Not wanting to give her dad any ammunition to use over custody in the divorce, Bonnie arranges the purchase of a gun online and rides her bike to buy the old .38 pistol. The desperate-for-drugs seller won't heed turning the deal down with $500 at stake, so Bonnie gets her gun, but sadly, so does Kerrigan.

A friend of Junior’s (John Clarence Stewart) drops by to tell his buddy from the shelter about the gun purchase that should never have happened.

He turns informant for the team in an effort to stop more tragedy.

The teenager does a good job of keeping her story straight in front of dad when Steve McGarrett (Alex O'Loughlin) and Danny (Scott Caan) question her after Kerrigan is found dead after early morning drinking on the beach. She denies even knowing the deceased until Facebook photos show her with mom and Kerrigan.

She then confides the truth but contends that she never shot Kerrigan. Not wanting “to see my mom any less than I already do,” Bonnie concocts her plan to shoot the abuser before he kills her mom, but dad gets summoned into early intervention.

When Owen is arrested and interrogated, he relates getting a call from his ex-wife, in terror of Kerrigan, and explaining how he stole money from Bonnie.

Owen goes to “have a word” with Kerrigan in the strongest sense and shoots him while trying to wrangle the gun. The story of the weapon is far from over.

Learning what it is to serve

The scene switches to a 911 call made by a young criminal, Hester (Colin Cunningham). Two officers arrived on the scene one being the young officer, Duke Lukela (Eric Elizaga). Thinking they are there for an animal cleanup, Hester ambushes them, killing Duke’s partner, and shooting Duke himself. Moving to a related scene, six-year-old Steve McGarrett (Revel Kolohe Sloboda) is watching television on a quiet night at home when his father, John (Ryan Bittle) is called to the dangerous scene. He tries to reason with Hester, but there can be none of that.

He is saved by his bulletproof vest and intercedes to save Duke’s life. He later explains to his young son that his work is dangerous because of “bad people” but he always works to help others.

Danny Williams opens another scene, set the night before he was officially sworn in for “Hawaii Five-O” duty, not even issued with his badge yet. He goes to a convenience store, in search of “something from a cow” for his evening meal when a robbery occurs, with the shooter using the same .38 that almost took Duke and John McGarrett. “Danno” makes a valiant effort to chase the shooter and save the wounded clerk, who dies en route to the hospital. No leads lead to meaningful results while Danny worked the case for years.

Tani (Meaghan Rath) has a very personal connection with the deadly weapon, too, as the scene switches to her earlier days of being involved with Damien (Jon Chaffin) her criminally-connected boyfriend back in 2015. She comes home to find her brother, Koa (Kunal Sharma) having too much fun with shooting practice with the famed weapon. Despite Damien taking the weapon away from the young man's hand, he hands the got off to another unsavory assailant who is later involved in a murder. Tani has the good sense to break off those relationships and six weeks later, joins the police force and finds that despite her short stay, she has the perfect attitude for “Hawaii Five-O.”

These fateful encounters do not come to light until Jerry (Jorge Garcia) pulls the records that reveal the 14 cases traced to the same weapon, and to so many lives on “Hawaii Five-O.” In a very moving scene, Commander McGarrett tells Duke how he learned “about something bigger than himself” from the late-night talk with his father, and the moment planted the seed of service.

Now that they had a serial number, the team set out to bring justice to those who had handled this weapon. Steve and Duke traveled to California to ensure that Hester met his fate. The robber in the convenience store was now a converted pastor but still could not escape consequences from his past. Finally, Bonnie and her mother were guided to a path for a more peaceful life, and hopefully, the judge granted self-defense for dad.

The final scene shows the “community gun” that wrought such havoc being placed permanently into evidence, enclosed safely in a box. The lives of those in “Hawaii Five-O” so affected by the same weapon continue to serve and protect.

After savoring this layered episode, the only sad truth for fans is that just two episodes remain in Season 9, but there is still hope for a Season 10.