As Magnum tries to keep his new relationship a secret and handle his cases solo, he's now looking for a single mom being hunted by two very dangerous killers. A misstep abroad forces Higgins to become involved with an old employer.
While Magnum and Higgins reunite and work the case of a construction worker's tragic death, TC and Shammy get skyjacked by a pair of drug runners posing as tourists.
When Magnum and Higgins are hired by an anxious groom to look into his bride-to-be on the eve of their wedding, what they think is a simple case of cold feet turns into a web of lies.
A journalist hires Magnum to track down his anonymous source after they mysteriously go dark. Higgins receives a new assignment from MI-6. Rick's old friend comes to the island, but TC is suspicious of his motives.
When Rick is asked to assist with a federal investigation of Robbie, Magnum launches his own investigation. Higgins is hired to investigate the disappearance of a retirement community resident's life savings.
Magnum starts following Higgins to discover what she's been hiding, as she's secretly assigned to infiltrate a group threatening to take down MI-6. Rick struggles after an explosion takes the life of someone important to him.
When a woman hires Magnum and Higgins to locate a man she met briefly at a coffee shop and felt a spark with, they learn that he is hiding a big secret.
A nun hires Magnum and Higgins to investigate a mysterious cash donation made to a parishioner undergoing medical treatment at the church. Jin's new dog walking business takes a dramatic turn.
Shammy asks Magnum and Higgins to locate his missing friend, a homeless veteran. T.C. tries to get Cade to return to school, but quickly learns it's not that simple.
When Hawaii Supreme Court nominee Judge Rachel Park is being blackmailed, she hires Magnum and Higgins who go to extraordinary lengths to help her out.
A bail bondsman hires Magnum and Higgins to track down a woman who skipped out on her $250,000 bond. T.C. and Katsumoto team up on an emotional search for Cade's mother.
When Magnum balks at notorious crime boss Osi Shima's 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.
The mother of a suspected bomber hires the team to locate her son and turn him in to the authority. Kumu and Rick help T.C. navigate his guilty conscience when he runs in to an old flame.
Higgins is in a complicated situation when 12-year-old Ella asks for help cracking a triple homicide that involves her mother. Magnum bonds with a terminally ill veteran and attempts to reunite him with his estranged family.
A disoriented man hires Magnum and Higgins to investigate a crime he doesn't remember after he woke up on the beach covered in blood. TC is taken aback when Cade's biological grandmother makes a surprise visit.
Magnum and Higgins are sent on a deadly mission inside a high security correctional center when a ruthless criminal abducts Katsumoto and his ex-wife, Beth.