A decorated former Navy SEAL who, upon returning home from Afghanistan, repurposes his military skills to become a private investigator in Hawaii.

Magnum, flooded with memories of his tour in Afghanistan, helps his fallen friend’s brother search for a now-grown Afghan boy who may have been a victim of trafficking.

Magnum helps Dan, a struggling fisherman and fellow veteran, when his 300-pound tuna worth $350,000 is stolen, and he discovers that the thief needs Magnum's help as well.

As their wedding day approaches, Magnum and Higgins help a modern-day Robin Hood who, thinking she was helping a school obtain needed supplies, unknowingly stole illicit drugs. Also, Rick helps a retired soldier with the difficult task of re-entering the work force as a civilian.

TC asks Magnum to take on a case to help acquit the father of one of his young football players, who is accused of murder.

Magnum and Higgins search for a CEO who has mysteriously vanished. Rick braces for a visit from his wild-child little sister, Ruthie.

Magnum takes a case from fellow private investigator Luther Gillis to find the true identity of a man’s comatose fiancée when he learns that she’s had extensive facial surgery.

A close friend of Higgins, an art connoisseur who recently hired Magnum to test his security, is murdered, and Thomas is arrested as the main suspect.

A man dying of lymphoma hires Magnum to find his estranged, bone-marrow-compatible brother who turns out to need Magnum’s help as well. Also, Magnum’s case brings back haunted memories for the guys of a past SEAL team mission that went sideways.

Magnum and Higgins help an up-and-coming mixed martial arts fighter who is being pressured by a gang to throw an illegal fight. Also, Kumu is arrested for stealing an artifact from a collector that should be returned to its original resting place.

Magnum and Higgins are hired to find a missing gamer whose online friends believe he might be in trouble. Jin Jeong enlists the help of TC in a treasure hunt after his ex-partner gets out of prison.

An aging tycoon asks Magnum to find his lost love who he says just recently contacted him; the only problem is she died 30 years ago. Also, Rick and TC meet a fellow vet who is having a hard time adjusting to civilian life.

As Magnum helps a woman find her missing cousin, Sergei, a Russian fugitive, Higgins' and Kumu's lives are put in danger when they get too close to the case.

While Magnum and Higgins are undercover as a couple on a romantic bus tour working a case, they must switch gears when one of the love birds on the trip is murdered and evidence is quickly deteriorating in the Hawaiian heat.

Magnum and Higgins take the case of recovering the stolen urn of a woman's deceased husband, but they soon find that others believe the urn is worth killing for. Also, Rick and TC confront a man who's been impersonating football legend Andre Reed.

Magnum and Higgins are each hired by a different spouse who are in the middle of a contentious divorce to dig up dirt on the other, and Thomas and Higgins soon find themselves competing over resources. Also, Rick and TC look into the death of an unidentified man and must share the news with his estranged daughter.

When a young man in need of immediate emergency surgery goes missing with a bullet lodged in his chest, Ethan asks Magnum and Higgins to find him before it’s too late. Also, TC talks to a military recruit who may be enlisting for the wrong reasons.

As Magnum and Higgins work a case to recover valuable stolen truffles, they also must care for a baby left abandoned at the gates of their estate, while Kumu tries to locate the infant’s mother.

Magnum’s Uncle Bernardo visits and reveals a shocking secret about Thomas’ mother. Also, TC asks Higgins for help when he realizes he may have witnessed a potential murder from his helicopter, Higgins decides it’s time to tell Ethan the truth about her past and TC offers Shammy the opportunity to become a pilot.

Magnum must help Rick’s crush, Toni, after her illegal poker game, organized to pay back a mob debt, is robbed by masked gunmen.

Magnum and Higgins' new partnership is tested when they disagree about being hired by a woman who wants them to recover her $3 million in stolen drug money in order to save her husband's life.

A guilt-ridden Magnum follows the clues his private investigator friend, Harry Brown, left behind when he was shot while working a case Thomas passed onto him. Also, TC helps Kumu lead a protest against construction on a Hawaiian sacred site.

When Junior is kidnapped as leverage to retrieve the stolen list of undercover CIA agents, and most of Five-0 is rounded up by the CIA to prevent them from interfering, Tani and Quinn ask Magnum and Higgins for their help. The crossover starts on Hawaii Five-0 S10E12 Ihea ‘oe i ka wa a ka ua e loku ana? (Where were you when the rain was pouring?) (I).

Magnum and TC go undercover as efficiency experts when a corporate manager is murdered and everyone in the office is a suspect. Also, Rick is curious why Higgins faked an injury to prevent her from investigating the case with Thomas

When Jin learns that an innocent woman is the target of a deadly hit, he asks Magnum and Higgins to help save her.