While Magnum waits for Higgins to decide if she'll officially become his partner, he takes the case of a missing wife who witnessed her boss' murder during a bank robbery. Also, Rick makes a big decision about his career.
An incorrigible pickpocket, Jin (guest star Bobby Lee), 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.
Kumu and Higgins are in danger when Robin's Nest is under siege by mercenaries storming the estate in order to find out the true identity of the White Knight, Robin's muse and literary hero. Also, Rick and T.C. helps one of Rick's employees (guest star WBC Heavyweight Champion Deontay Wilder) when his car is stolen, and Higgins finally gives Magnum an answer about if she'll become his partner.
When Katsumoto suspects that one of his fellow cops is dirty and has stolen evidence, he begrudgingly asks Magnum and Higgins for help. Also, Rick and TC help Los Angeles Rams defensive tackle Aaron Donald when his tablet, that contains the Rams' playbook is stolen.
On Halloween, Magnum and Jin (guest star Bobby Lee) 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.
Magnum must help his defense attorney girlfriend, Abby Miller (guest star Brooke Lyons), when she realizes that the client she successfully defended in a murder trial is actually guilty.
Jay Hernandez
Thomas Magnum
Perdita Weeks
Juliet Higgins
Zachary Knighton
Rick Wright
Stephen Hill
Theodore 'T.C' Calvin
Amy Hill
Teuila 'Kumu' Tuileta