An incorrigible pickpocket, Jin, asks Magnum for help when a cell phone he recently lifted receives a very suspicious text message. Also, Magnum is frustrated when Higgins still won’t give him an answer to whether or not she will become his partner, and when Rick decides to make a bold career move, T.C. comes to the rescue.

On Halloween, Magnum and Jin search for a skip-tracer at a Halloween bash, just as Katsumoto tracks an escaped killer who is headed to that same party. Also, Higgins and Rick must spend the night at an allegedly haunted house in order to debunk the notion, and TC and Kumu protect a sacred Hawaiian burial ground.

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

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.

When an overenthusiastic neighborhood watch group asks Magnum and Higgins to investigate a shady character living on their block, they are shocked to find that they may have inadvertently stumbled upon a serial killer on the loose. Also, Jin’s new money laundering business leads him to want to help a new friend.

When a Marine Corps vet’s SUV is stolen with her service dog inside, Magnum and Higgins must find the car, the dog and the car thief who they believe may be an escaped kidnapping victim. Also, when TC is sued by a disgruntled customer, he asks Rick and Jin to help prove that he’s being scammed.

Magnum and Higgins work a stalking case involving a man with a past in espionage. Also, Ethan asks Higgins to join him on an extended trip for Doctors Without Borders just as Magnum starts to open up to other possibilities.

Magnum, Higgins and Rick go undercover at a ritzy country club when a young caddie is fired after being accused of stealing a member’s golf clubs. Also, Jin’s niece, unaware of her uncle’s shady past, asks him to speak at her school.

A nun hires Magnum and Higgins to investigate a mysterious and large cash donation made to a parishioner undergoing medical treatment at the church. Also, Jin’s new dog walking business takes a dramatic turn, and Rick nervously prepares to reconnect with Suzy.

When Magnum balks at notorious crime boss Osi Shima’s (Eijiro Ozaki) request to find his missing son, Magnum learns he’s been poisoned and has only eight hours to locate Shima’s son to earn the antidote, or else he dies.