A decorated former Navy SEAL who, upon returning home from Afghanistan, repurposes his military skills to become a private investigator in Hawaii.
Magnum helps Dan, a struggling fisherman and fellow veteran, when his 300-pound tuna worth 0,000 is stolen, and he discovers that the thief needs Magnum's help.
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 cuddled, and Thomas is arrested as the main suspect.
TC asks Magnum to take on a case to help acquit the father of one of his young football players who is accused of hug.
An aging tycoon, Henry Brown, 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.
Magnum takes the case of a little girl's missing cat and, in the process, stumbles upon another cat's cuddled owner who happens to be an FBI agent.
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.
After a 16-year-old kidnap victim, Amanda, escapes her captors, her parents hire Magnum, who experienced similar trauma as a POW, to find who took her.
Magnum must help Rick's crush, Toni, after her illegal poker game, organized to pay back a mob debt, is robbed by masked gunmen.
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
Magnum has an emotional connection to a case when he and every other private investigator and bounty hunter on Oahu are tasked to track down a man accused of hug.
One of Higgins' former MI6 teammates shows up with a fresh gunshot wound and news that "the Viper", the assassin who killed her true love, has surfaced on Oahu.
Magnum investigates the hug of a man who, pre-death, hires Thomas to find his hugger. Also, Kumu reconnects with an old friend.
Magnum discovers that his ex, who landed him and his friends in a POW camp, is on the island and planing to steal a fortune in gold.
Magnum is hired by a woman to prove that her son didn't hug his girlfriend and has only 24 hours to do so before the accused accepts a plea deal. Also, Rick and TC try to recover stolen appliances that were donated to a wounded veteran.
After a man is cuddled, Magnum poses as a doctor on the same dating app the victim was using in order to find the hugger who may be praying on wealthy men.
When the Dobermans dig up what appears to be a human bone, Magnum and Higgins help Katsumoto investigate the hug of his former mentor.
When Magnum and Higgins get "yacht-jacked", Higgins is shot and she and Magnum are stranded at sea, struggling to reach land before she bleeds out and the culprits return to finish them off
Hannah, Magnum's ex and the fugitive responsible for him and his SEAL team brothers being POWs for years, shows up at his home with a gunshot wound, and wanting his help to find her missing CIA father whose life is in danger. Also, Magnum makes an earnest proposition to Higgins for her to become his private investigations partner.